text: 2020 Boulanger, E., et al. "Spatial graphs highlight how multi-generational dispersal shapes landscape genetic patterns." Ecography (2020). Résumé: Current approaches that compare spatial genetic structure of a given species and the dispersal of its mobile phase can detect a mismatch between both patterns mainly due to processes acting at different temporal scales. Genetic structure result from gene flow and other evolutionary and demographic processes over many generations, while dispersal predicted from the mobile phase often represents solely one generation on a single time-step. In this study, we present a spatial graph approach to landscape genetics that extends connectivity networks with a stepping-stone model to represent dispersal between suitable habitat patches over multiple generations. We illustrate the approach with the case of the striped red mullet Mullus surmuletus in the Mediterranean Sea. The genetic connectivity of M. surmuletus was not correlate with the estimated dispersal probability over one generation, but with the stepping-stone estimate of larval dispersal, revealing the temporal scale of connectivity across the Mediterranean Sea. Our results highlight the importance of considering multiple generations and different time scales when relating demographic and genetic connectivity. The spatial graph of genetic distances further untangles intra-population genetic structure revealing the Siculo-Tunisian Strait as an important corridor rather than a barrier for gene flow between the Western- and Eastern Mediterranean basins, and identifying Mediterranean islands as important stepping-stones for gene flow between continental populations. Our approach can be easily extended to other systems and environments. Mots-Clés: connectivity; fish populations; flow; genetic connectivity; habitat; Mediterranean Sea; migration rates; models; Mullus surmuletus; mullus-surmuletus; ocean currents; r-package; seascape genetics; spatial graphs; stepping-stone dispersal; unsampled populations Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Feuilloley, G., et al. "Concomitant changes in the environment and small pelagic fish community of the Gulf of Lions." Prog. Oceanogr.. 186 (2020): 102375. Résumé: An important decrease in small pelagic fish condition and size has been observed in the most productive ecosystem of the Mediterranean Sea, the Gulf of Lions, since 2008, leading to an important fishery crisis. Previous studies suggested bottom-up control to be the most probable cause for these changes. Here, we investigate whether an environmental change might have caused such a situation. In the absence of zooplankton time series, this study aims at describing temporal changes in key abiotic factors for the planktonic and fish production of the Gulf of Lions, such as SST, meso-scale fronts, wind-induced coastal upwelling, river discharge, water stratification and deep convection and then at understanding potential link on Chl-a concentration as well as small pelagic fish populations. Our results indicate that the environmental conditions have broadly changed in the Gulf of Lion, with a major change in the mid-2000s, affecting the Chla concentration (which showed a regime shift in 2007), but also the SST, the upwelling and frontal activities, the Rhone river discharge (and particularly the N and P nutrients inputs) as well as the deep winter convection. Those changes could have affected the plankton production and consequently the small pelagic fish community that displayed similar patterns of variations as the environmental conditions. Mots-Clés: algorithm; anchovy; Bottom-up control; Chlorophyll-a; circulation; climate; Environmental change; fronts; mediterranean sea; Northwestern Mediterranean Sea; oscillation; planktonic ecosystem; pressure; Small pelagic fish; variability Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Pagès, R., et al. "Changes in rivers inputs during the last decades significantly impacted the biogeochemistry of the eastern Mediterranean basin: A modelling study." Prog. Oceanogr.. 181 (2020): 102242. Résumé: The Mediterranean Sea (MS) is a semi-enclosed sea characterized by a zonal west-east gradient of oligotrophy, where microbial growth is controlled by phosphate availability in most situations. External inputs of nutrients including Gibraltar inputs, river inputs and atmospheric deposition are therefore of major importance for the biogeochemistry of the MS. The latter has long been considered to be driven mainly by nutrient exchanges at Gibraltar. However, recent studies indicate that river inputs significantly affect nutrients concentrations in the Mediterranean Sea, although their resulting impact on its biogeochemistry remains poorly understood. In this study, our aim was to help fill this knowledge gap by addressing the large-scale and long-term impact of variations in river inputs on the biogeochemistry of the Mediterranean Sea over the last decades, using a coupled physical-biogeochemical 3D model (NEMO-MED12/Eco3M-Med). As a first result, it has been shown by the model that the strong diminution (60%) of phosphate (PO4) in river inputs into the Mediterranean Sea since the end of the 1980s induced a significant lowering of PO4 availability in the sub-surface layer of the Eastern Mediterranean Basin (EMB). One of the main consequences of PO4 diminution is the rise, never previously documented, of dissolved organic carbon (DOC) concentrations in the surface layer (by 20% on average over the EMB). Another main result concerns the gradual deepening of the top of the phosphacline during the period studied, thus generating a shift between the top of the nitracline and the top of the phosphacline in the EMB. This shift has already been observed in situ and documented in literature, but we propose here a new explanation for its occurrence in the EMB. The last main result is the evidence of the decline in abundance and the reduction of size of copepods calculated by the model over the years 1985-2010, that could partially explain the reduction in size of anchovy and sardine recently recorded in the MS. In this study, it is shown for the first time that the variations in river inputs that occurred in the last decades may have significantly altered the biogeochemical cycles of two key elements (P and C), in particular in the EMB. To conclude, the magnitude of the biogeochemical changes induced by river inputs and runoff alone over the last thirty years clearly calls for the use of realistic scenarios of river inputs along with climate scenarios for coupled physical-biogeochemical forecasts in the MS. Mots-Clés: Biogeochemistry; Coupled physical-biogeochemical model; ecosystem changes; Flexible stoichiometry model; Mediterranean Sea; nitrogen; Nutrient; nutrients; organic-carbon; phosphate; phosphorus limitation; phytoplankton; primary productivity; River inputs; sea; western Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML 2019 Benedetti, F., et al. "Climate change may have minor impact on zooplankton functional diversity in the Mediterranean Sea." Divers. Distrib.. 25.4 (2019): 568–581. Résumé: Aim To assess the impact of climate change on the functional diversity of marine zooplankton communities. Location The Mediterranean Sea. Methods We used the functional traits and geographic distributions of 106 copepod species to estimate the zooplankton functional diversity of Mediterranean surface assemblages for the 1965-1994 and 2069-2098 periods. Multiple environmental niche models were trained at the global scale to project the species habitat suitability in the Mediterranean Sea and assess their sensitivity to climate change predicted by several scenarios. Simultaneously, the species traits were used to compute a functional dendrogram from which we identified seven functional groups and estimated functional diversity through Faith's index. We compared the measured functional diversity to the one originated from null models to test if changes in functional diversity were solely driven by changes in species richness. Results All but three of the 106 species presented range contractions of varying intensity. A relatively low decrease of species richness (-7.42 on average) is predicted for 97% of the basin, with higher losses in the eastern regions. Relative sensitivity to climate change is not clustered in functional space and does not significantly vary across the seven copepod functional groups defined. Changes in functional diversity follow the same pattern and are not different from those that can be expected from changes in richness alone. Main conclusions Climate change is not expected to alter copepod functional traits distribution in the Mediterranean Sea, as the most and the least sensitive species are functionally redundant. Such redundancy should buffer the loss of ecosystem functions in Mediterranean zooplankton assemblages induced by climate change. Because the most negatively impacted species are affiliated to temperate regimes and share Atlantic biogeographic origins, our results are in line with the hypothesis of increasingly more tropical Mediterranean communities. Mots-Clés: biogeography; calanus-helgolandicus; climate change; communities; conservation; fish assemblages; framework; functional diversity; future; marine biodiversity; Mediterranean Sea; niche modelling; null model; ocean; trait; zooplankton Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Gerigny, O., et al. "Seafloor litter from the continental shelf and canyons in French Mediterranean Water: Distribution, typologies and trends." Mar. Pollut. Bull.. 146 (2019): 653–666. Résumé: Seafloor litter has been studied both on the continental shelves (by trawling during 24 years) and in canyons (by ROV) of the French Mediterranean sea Water (FMW). On the continental shelf, mean densities range from 49.63 to 289.01 items/km(2). The most abundant categories were plastic, glass/ceramics, metals and textiles. Trend analysis shows a significant increase in plastic quantities during the study period. Plastics accumulate at all depths, with heavier items being found in deeper areas, while the continental slope-break appears as a clean area. The spatial distribution of litter revealed the influence of geomorphologic factors, anthropic activities, shipping route, river inputs. All the canyons are affected by debris but coastal canyons (Ligurian Sea and Corsica) were more impacted than offshore canyons in the Gulf of Lion. The FMW appears to be highly polluted with regard to values found in other areas, but lower than those observed in the Eastern Mediterranean. Mots-Clés: abundance; adriatic sea; areas; benthic marine litter; Canyon; Corsica; gulf; Gulf of Lion; impacts; macro; Marine litter; Mediterranean Sea; northern; plastic debris; Seafloor; strategy Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Hidalgo, M., et al. "Size-dependent survival of European hake juveniles in the Mediterranean Sea." Sci. Mar.. 83 (2019): 207–221. Résumé: Most studies on European hake focus on the recruitment process and nursery areas, whereas the information is comparatively limited on the ecology of the juvenile stage (ca. second year of life)-the one most exploited by the Mediterranean trawl fisheries. Using information of the MEDITS programme, we provide a spatial and temporal assessment of the influence of body size and growth on hake survival from recruits (age 0) to juveniles (age 1), along with the impact of surface temperature and chlorophyll variability. At a biogeographic scale, size-dependent survival is supported, with areas with higher mean length of recruits and juveniles yielding higher survival. A similar pattern was observed at interannual level in some western Mediterranean areas, also mediated by a density-dependent effect on growth. However, the most recurrent inter-annual pattern was a negative effect of size on survival, which could be attributed to potential ontogenetic changes in catchability and underrepresentation of intra-annual recruitment pulses that are seasonally inaccessible to the MEDITS survey. Results also evidence that survival in the Alboran and Adriatic seas is dependent on the primary production variability, and that Corsica and Sardinia could be potential feeding grounds receiving juveniles from neighbouring areas. The present study reveals the importance of size- and growth-dependent survival in the juvenile stage of European hake in the Mediterranean Sea. Mots-Clés: catchability; density; European hake; fisheries; growth; juvenile survival; life-history; management; Mediterranean Sea; merluccius-merluccius l.; natural mortality; population-structure; recruitment; size dependence Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Meddeb, M., et al. "A new type of plankton food web functioning in coastal waters revealed by coupling Monte Carlo Markov chain linear inverse method and ecological network analysis." Ecol. Indic.. 104 (2019): 67–85. Résumé: Plankton food webs (PFW) typology is based on different categories of functioning, according to the dominant processes and the role played by heterotrophic bacteria, small vs large phytoplankton, and small vs large zooplankton. Investigating the structure and the function of planktonic food webs in two SW Mediterranean waters (inshore and marine sites) at four seasons, using inverse (LIM-MCMC) and ecological network (ENA) analyses, we identified a new type of food web, called the "bacterial multivorous food web". This food web adds to the conventional trophic continuum as previously reported. The "bacterial multivorous food web" present in winter showed the lowest primary production among seasons, but highest bacterial production. Several food web ratios characterized this new typology e.g. picophytoplankton net primary production to total primary production varied from 0.20 to 0.28; bacterial to primary production ratio is higher than values reported in global scale (congruent to 1); bacterial net production to the potential protozoan prey net production was high (>0.2). In this special food web, carbon was mostly recycled, with a moderate fraction channeled to deep waters, which lead to a higher retention of carbon inside the ecosystem. This winter PFW also seemed to be the most organized, specialized, stable and mature, as related to common interpretations of ENA. The spring was characterized by herbivorous food web, with highest activity coinciding with low stability. Although less usual, the herbivorous pathway was also observed during summer, in inshore waters. The autumn food webs, which functioned as multivorous or microbial food webs, appeared to be stable and mature. Finally, our study demonstrates the usefulness of food web models derived ratios combined with ecological network analysis indices to conduct evaluation of the structure and functioning of ecosystems and potentially to support management decisions in marine environment. Mots-Clés: Bacterial multivorous food web; biogenic carbon; Coastal waters; continental-shelf; Ecology; ecosystem attributes; flow networks; Food web modeling; grazing impact; gulf; mediterranean sea; model analysis; Network analysis; Seasonal variations; seasonal-dynamics; trophic network; Trophic structure Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Pagès, R., et al. "Changes in rivers inputs during the last decades significantly impacted the biogeochemistry of the eastern Mediterranean basin: a modelling study." Progress in Oceanography (2019): 102242. Résumé: The Mediterranean Sea (MS) is a semi-enclosed sea characterized by a zonal west-east gradient of oligotrophy, where microbial growth is controlled by phosphate availability in most situations. External inputs of nutrients including Gibraltar inputs, river inputs and atmospheric deposition are therefore of major importance for the biogeochemistry of the MS. This has long been considered to be driven mainly by nutrient exchanges at Gibraltar. However, recent studies indicate that river inputs significantly affect nutrients concentrations in the Mediterranean Sea, although their resulting impact on its biogeochemistry remains poorly understood. In this study, our aim was to make good this lack by addressing the large-scale and long-term impact of variations in river inputs on the biogeochemistry of the Mediterranean Sea over the last decades, using a coupled physical-biogeochemical 3D model (NEMO-MED12/Eco3M-Med). As a first result, it has been shown by the model that the strong diminution (60 %) of phosphate (PO4) in river inputs into the Mediterranean Sea since the end of the 1980s induced a significant lowering of PO4 availability in the sub-surface layer of the Eastern Mediterranean Basin (EMB). One of the main consequences of PO4 diminution is the rise, never previously documented, of dissolved organic carbon (DOC) concentrations in the surface layer (by 20% on average over the EMB). Another main result concerns the gradual deepening of the top of the phosphacline during the period studied, thus generating a shift between the top of the nitracline and the top of the phosphacline in the EMB. This shift has already been observed in situ and documented in literature, but we propose here a new explanation for its occurrence in the EMB. The last main result is the evidence of the decline in abundance and the reduction of size of copepods calculated by the model over the years 1985-2010, that could partially explain the reduction in size of anchovy and sardine recently recorded in the MS. In this study, it is shown for the first time that the variations in river inputs that occurred in the last decades may have significantly altered the biogeochemical cycles of two key elements (P and C), in particular in the EMB. To conclude, the magnitude of the biogeochemical changes induced by river inputs and runoff alone over the last thirty years clearly calls for the use of realistic scenarios of river inputs along with climate scenarios for coupled physical-biogeochemical forecasts in the MS. Mots-Clés: Biogeochemistry; Coupled physical-biogeochemical model; Flexible stoichiometry model; Mediterranean Sea; Nutrient; River inputs Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Queiros, Q., et al. "Food in the sea: size also matters for pelagic fish." Front. Mar. Sci.. 6 (2019): Unsp-385. Résumé: Small pelagic fish are key components of marine ecosystems and fisheries worldwide. Despite the absence of recruitment failure and overfishing, pelagic fisheries have been in crisis for a decade in the Western Mediterranean Sea because of a marked decline in sardine size and condition. This situation most probably results from bottom-up control and changes in the plankton community toward smaller plankton. To understand such an unusual phenomenon, we developed an original and innovative experimental approach investigating the mechanisms induced by a reduction in the quantity and size of sardine prey. While experimentations offer the unique opportunity to integrate behavior and ecophysiology in understanding key demographic processes, they remain rarely used in fisheries science, even more so on small pelagics due to the notorious difficulty to handle them. The results revealed that food size (without any modification of its energy content) is as important as food quantity for body condition, growth and reserve lipids: sardines that fed on small particles had to consume twice as much as those feeding on large particles to achieve the same condition and growth. Such a strong impact of food size (based on 100 vs. 1200 mu m pellets) was unexpected and may reflect a different energy cost or gain of two feeding behaviors, filter-feeding vs. particulate-feeding, which would have to be tested in further study. As increasing temperature favors planktonic chains of smaller size, climate change might actually accelerate and amplify such phenomenon and thus strongly affect fisheries. Mots-Clés: anchovy; body condition; bottom-up; bottom-up control; experimentation; feeding-behavior; gulf; lions; mediterranean sea; oxidative stress; respiration rate; Sardina pilchardus; sardine sardina-pilchardus; small pelagics; swimming speed Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Saraux, C., et al. "Small pelagic fish dynamics: A review of mechanisms in the Gulf of Lions." Deep-Sea Res. Part II-Top. Stud. Oceanogr.. 159 (2019): 52–61. Résumé: Around 2008, an ecosystem shift occurred in the Gulf of Lions, highlighted by considerable changes in biomass and fish mean weight of its two main small pelagic fish stocks (European anchovy, Engraulis encrasicolus; European sardine, Sardina pilchardus). Surprisingly these changes did not appear to be mediated by a decrease in fish recruitment rates (which remained high) or by a high fishing pressure (exploitation rates being extremely low). Here, we review the current knowledge on the population's dynamics and its potential causes. We used an integrative ecosystem approach exploring alternative hypotheses, ranging from bottom-up to top-down control, not forgetting epizootic diseases. First, the study of multiple population characteristics highlighted a decrease in body condition for both species as well as an important decrease in size resulting from both a slower growth and a progressive disappearance of older sardines. Interestingly, older sardines were more affected by the decrease in condition than younger ones, another sign of an unbalanced population structure. While top-down control by bluefin tuna or dolphins, emigration and disease were mostly discarded as important drivers, bottom-up control mediated by potential changes in the plankton community appeared to play an important role via a decrease in fish energy income and hence growth, condition and size. Isotopic and stomach content analyses indicated a dietary shift pre- and post-2008 and modeled mesozooplankton abundance was directly linked to fish condition. Despite low energy reserves from 2008 onwards, sardines and anchovies maintained if not increased their reproductive investment, likely altering the life-history trade-off between reproduction and survival and resulting in higher natural mortality. The current worrying situation might thus have resulted from changes in plankton availability/diversity, which remains to be thoroughly investigated together with fish phenotypic plasticity. Mots-Clés: Population dynamics; Zooplankton; anchovy; fisheries; history; forage fish; nw mediterranean sea; el-nino; fluctuations; body condition; Bottom-up; Disease; Exploited species; Top-down; sardine sardinops-sagax; southern benguela Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Sbrana, M., et al. "Spatiotemporal abundance pattern of deep-water rose shrimp, Parapenaeus longirostris, and Norway lobster, Nephrops norvegicus, in European Mediterranean waters." Sci. Mar.. 83 (2019): 71–80. Résumé: The main characteristics concerning the distribution of two of the most important decapod crustaceans of commercial interest in the Mediterranean Sea, the deep-water rose shrimp, Parapenaeus longirostris, and the Norway lobster. Nephrops norvegicus, are studied in the European Mediterranean waters. The study is based on data collected under the MEDITS trawl surveys from 1994 to 2015 from the Gibraltar Straits to the northeastern Levantine Basin (Cyprus waters). The observed differences can be interpreted as different responses to environmental drivers related to the differing life history traits of the two species. In fact, N. norvegicus is a long-living, benthic burrowing species with low growth and mortality rates, while P. longirostris is an epibenthic, short-living species characterized by higher rates of growth and mortality. Mots-Clés: 1846 decapoda; atlantic; catch; crustacea; distribution; dynamics; fishery; lucas; Mediterranean Sea; merluccius-merluccius; Nephrops norvegicus; Parapenaeus longirostris; population; trawl survey; tyrrhenian sea Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Sion, L., et al. "Spatial distribution pattern of European hake, Merluccius merluccius (Pisces: Merlucciidae), in the Mediterranean Sea." Sci. Mar.. 83 (2019): 21–32. Résumé: The present study provides updated information on the occurrence, abundance and biomass distribution patterns and length frequencies of Merluccius merluccius in the Mediterranean Sea, by analysing a time series of data from the Mediterranean International Trawl Surveys (MEDITS) from 1994 to 2015. The highest values of abundance and biomass were observed in the Sardinian Seas. The use of a generalized additive model, in which standardized biomass indices (kg km(-2)) were analysed as a function of environmental variables, explained how ecological factors could affect the spatio-temporal distribution of European hake biomass in the basin. High biomass levels predicted by the model were observed especially at 200 m depth and between 14 degrees C and 18 degrees C, highlighting the preference of the species for colder waters. A strong reduction of biomass was observed since the year 2009, probably due to the strengthening of the seasonal thermocline that had greatly reduced the availability of food. The general decrease in biomass of several stocks of anchovy and sardine, preys of European hake, might be indirectly connected to the decreasing biomass detected in the present study. The length analysis shows median values lower than 200 mm total length of most of the investigated areas. Mots-Clés: areas; biology; distribution pattern; environmental factors; gadiformes; l. recruitment; Mediterranean Sea; medits; Merluccius merluccius; small pelagic fish; spatiotemporal distribution; variability Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Spedicato, M. T., et al. "Spatial distribution of marine macro-litter on the seafloor in the northern Mediterranean Sea: the MEDITS initiative." Sci. Mar.. 83 (2019): 257–270. Résumé: Marine litter is one of the main sources of anthropogenic pollution in the marine ecosystem, with plastic representing a global threat. This paper aims to assess the spatial distribution of plastic macro-litter on the seafloor, identifying accumulation hotspots at a northern Mediterranean scale. Density indices (items km(-2)) from the MEDITS trawl surveys (years 2013-2015) were modelled by generalized additive models using a Delta-type approach and several covariates: latitude, longitude, depth, seafloor slope, surface oceanographic currents and distances from main ports. To set thresholds for the identification of accumulation areas, the percentiles (85th, 90th and 95th) of the plastic spatial density distribution were computed on the raster data. In the northern Mediterranean marine macro-litter was widespread (90.13% of the 1279 surveyed stations), with plastic by far the most recurrent category. The prediction map of the plastic density highlighted accumulation areas (85th, 90th and 95th percentiles of the distribution, respectively, corresponding to 147, 196 and 316 items km(-2)) in the Gulf of Lions, eastern Corsica. the eastern Adriatic Sea, the Argo-Saronic region and waters around southern Cyprus. Maximum densities were predicted in correspondence to the shallower depths and in proximity to populated areas (distance from the ports). Surface currents and local water circulation with cyclonic and anticyclonic eddies were identified as drivers likely facilitating the sinking to the bottoms of floating debris Mots-Clés: abundance; accumulation; accumulation areas; adriatic sea; GAM modelling; general-circulation; habitats; impact; islands; marine macro-litter; Mediterranean Sea; medits; microplastics; plastic; plastic debris; transport Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML 2018 Ayata, S. - D., et al. "Regionalisation of the Mediterranean basin, a MERMEX synthesis." Progress in Oceanography. 163 (2018): 7–20. Résumé: Regionalisation aims at delimiting provinces within which physical conditions, chemical properties, and biological communities are reasonably homogeneous. This article proposes a synthesis of the many recent regionalisations of the open-sea regions of the Mediterranean Sea. The nine studies considered here defined regions based on different, and sometimes complementary, criteria: dynamics of surface chlorophyll concentration, ocean currents, three-dimensional hydrological and biogeochemical properties, or the distribution of organisms. Although they identified different numbers and patterns of homogeneous regions, their compilation in the epipelagic zone identifies nine consensus frontiers, eleven consensus regions with relatively homogeneous conditions, and four heterogeneous regions with highly dynamical conditions. The consensus frontiers and regions are in agreement with well-known hydrodynamical features of the Mediterranean Sea, which constrain the distribution of hydrological and ecological variables. The heterogeneous regions are rather defined by intense mesoscale activity. The synthesis proposed here could constitute a reference step for management actions and spatial planning, such as the application of the European Marine Strategy Framework Directive, and for future biogeochemical and ecological studies in the Mediterranean Sea. Mots-Clés: Mediterranean Sea; regionalisation; biogeochemistry; circulation; mesoscale features; epipelagic ocean; management; spatial planning Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Benedetti, F., et al. "Do functional groups of planktonic copepods differ in their ecological niches?" J. Biogeogr.. 45.3 (2018): 604–616. Résumé: Aim: To assess the degree of overlap between the environmental niches of marine planktonic copepods and test if the distribution of copepod functional groups differs across environmental gradients. Location: The Mediterranean Sea. Methods: Functional groups were defined based on clustering of functional traits in 106 marine copepod species using a multivariate ordination analysis. Functional traits included maximum body length, feeding mode, spawning strategy and trophic group. Simultaneously, the global distribution of the species was used to model their environmental niches with six environmental variables. For each of these predictors, four niche parameters were derived from the univariate response curve of each species to summarise their environmental preferences and ordinate the species in niche space through a PCA. Finally, the differences in the position in niche space of functional groups were tested with variance analysis. Results: We identified seven copepod functional groups with different distributions along the environmental gradients covered by our study. While carnivorous functional groups were affiliated with oligotrophic and tropical conditions, large and small current-feeding herbivores are associated with colder, more seasonally varying and productive conditions. Small cruising detritivores and other small current-feeding herbivores were not affiliated with specific conditions as their constituting species were scattered in niche space. Main conclusions: Since copepod functional groups occupy distinct ecological niches, ecosystem processes related to these groups are expected to vary across environmental gradients. Conditions favouring large current-feeding herbivores should allow for enhanced fluxes of energy and nutrients through Mediterranean Sea ecosystems, while such fluxes should be weakened where large carnivores and small passive ambush-feeding copepods dominate. Our study supports the development of trait-based zooplankton functional groups in marine ecosystem models. Mots-Clés: climate-change; copepods; species distribution models; north-atlantic; calanus-finmarchicus; mediterranean sea; environmental niche; functional groups; lipid pump; marine ecosystem; oithona-similis; pseudo-absences; trait biogeography; zooplankton; zooplankton fecal pellets Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Bouchoucha, M., et al. "Otolith fingerprints as natural tags to identify juvenile fish life in ports." Estuar. Coast. Shelf Sci.. 212 (2018): 210–218. Résumé: The construction of ports has caused substantial habitat destruction in coastal areas previously used as nursery grounds by many fish species, with consequences to fish stocks. These artificial coastal areas might provide alternative nursery habitats for several species for juvenile fish abundances and growth in ports, although their contribution to adult stocks had never been estimated. The variability of otolith composition in the juveniles of two Diplodus species was investigated in three contrasting port areas and two adjacent coastal juvenile habitats of the Bay of Toulon (northwestern Mediterranean) in order to determine the possible use of otolith fingerprints as natural tags for the identification of juvenile fishes in ports. The global accuracy of discrimination between ports and coastal areas was very high (94%) irrespective of species, suggesting that otolith fingerprints can be used with confidence to retrospectively identify past residency in the ports of this bay. However, Ba was systematically the most discriminating element, since its concentrations in otoliths were generally higher outside ports than in inside them, probably due to river runoff. Moreover, otolith signatures varied greatly by species and between sampling sites. Furthermore, although Cu and Pb concentrations in water were at least 2.3-34-fold higher inside ports than outside, this was not consistently reflected in fish otoliths, confirming that spatial differences in otolith concentrations depend on the species and do not directly reflect differences in environmental contamination levels. Therefore, it seems unlikely that otolith microchemistry could provide a universal fingerprint capable of discriminating ports from other coastal areas. Nevertheless, the contribution of ports to adult fish populations can be determined well by establishing a library of otolith fingerprints for all juvenile habitats. Mots-Clés: coastal habitats; Coastal areas; Contamination; elemental fingerprints; Fish; genus diplodus; la-icpms; nursery habitats; Nursery habitats; situ speciation measurements; sparid fishes; stable-isotopes; thin-films dgt; water chemistry; western mediterranean sea Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Calo, A., et al. "Use of Lagrangian simulations to hindcast the geographical position of propagule release zones in a Mediterranean coastal fish." Mar. Environ. Res.. 134 (2018): 16–27. Résumé: The study of organism dispersal is fundamental for elucidating patterns of connectivity between populations, thus crucial for the design of effective protection and management strategies. This is especially challenging in the case of coastal fish, for which information on egg release zones (i.e. spawning grounds) is often lacking. Here we assessed the putative location of egg release zones of the saddled sea bream (Oblada melanura) along the southeastern coast of Spain in 2013. To this aim, we hindcasted propagule (egg and larva) dispersal using Lagrangian simulations, fed with species-specific information on early life history traits (ELTs), with two approaches: 1) back-tracking and 2) comparing settler distribution obtained from simulations to the analogous distribution resulting from otolith chemical analysis. Simulations were also used to assess which factors contributed the most to dispersal distances. Back-tracking simulations indicated that both the northern sector of the Murcia region and some traits of the North-African coast were hydrodynamically suitable to generate and drive the supply of larvae recorded along the coast of Murcia in 2013. With the second approach, based on the correlation between simulation outputs and field results (otolith chemical analysis), we found that the oceanographic characteristics of the study area could have determined the pattern of settler distribution recorded with otolith analysis in 2013 and inferred the geographical position of main O. melanura spawning grounds along the coast. Dispersal distance was found to be significantly affected by the geographical position of propagule release zones. The combination of methods used was the first attempt to assess the geographical position of propagule release zones in the Mediterranean Sea for O. melanura, and can represent a valuable approach for elucidating dispersal and connectivity patterns in other coastal species. Mots-Clés: circulation; Mediterranean Sea; sea; dispersal; larval; habitat; marine protected areas; recruitment; variability; population connectivity; Dispersal distance; Lagrangian simulations; mesoscale eddies; Propagule release zones; Sea bream Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Courbin, N., et al. "Short-term prey field lability constrains individual specialisation in resource selection and foraging site fidelity in a marine predator." Ecol. Lett.. 21.7 (2018): 1043–1054. Résumé: Spatio-temporally stable prey distributions coupled with individual foraging site fidelity are predicted to favour individual resource specialisation. Conversely, predators coping with dynamic prey distributions should diversify their individual diet and/or shift foraging areas to increase net intake. We studied individual specialisation in Scopoli's shearwaters (Calonectris diomedea) from the highly dynamic Western Mediterranean, using daily prey distributions together with resource selection, site fidelity and trophic-level analyses. As hypothesised, we found dietary diversification, low foraging site fidelity and almost no individual specialisation in resource selection. Crucially, shearwaters switched daily foraging tactics, selecting areas with contrasting prey of varying trophic levels. Overall, information use and plastic resource selection of individuals with reduced short-term foraging site fidelity allow predators to overcome prey field lability. Our study is an essential step towards a better understanding of individual responses to enhanced environmental stochasticity driven by global changes, and of pathways favouring population persistence. Mots-Clés: behavior; Behavioural consistency; Calonectris diomedea; diet; ecology; foraging site fidelity; gannets; habitat selection; mediterranean sea; models; movement; resource selection; Scopoli's shearwater; seabirds; strategies; temporal resource dynamic; Western Mediterranean Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Dalongeville, A., et al. "Geographic isolation and larval dispersal shape seascape genetic patterns differently according to spatial scale." Evol. Appl.. 11.8 (2018): 1437–1447. Résumé: Genetic variation, as a basis of evolutionary change, allows species to adapt and persist in different climates and environments. Yet, a comprehensive assessment of the drivers of genetic variation at different spatial scales is still missing in marine ecosystems. Here, we investigated the influence of environment, geographic isolation, and larval dispersal on the variation in allele frequencies, using an extensive spatial sampling (47 locations) of the striped red mullet (Mullus surmuletus) in the Mediterranean Sea. Univariate multiple regressions were used to test the influence of environment (salinity and temperature), geographic isolation, and larval dispersal on single nucleotide polymorphism (SNP) allele frequencies. We used Moran's eigenvector maps (db-MEMs) and asymmetric eigenvector maps (AEMs) to decompose geographic and dispersal distances in predictors representing different spatial scales. We found that salinity and temperature had only a weak effect on the variation in allele frequencies. Our results revealed the predominance of geographic isolation to explain variation in allele frequencies at large spatial scale (>1,000km), while larval dispersal was the major predictor at smaller spatial scale (<1,000km). Our findings stress the importance of including spatial scales to understand the drivers of spatial genetic variation. We suggest that larval dispersal allows to maintain gene flows at small to intermediate scale, while at broad scale, genetic variation may be mostly shaped by adult mobility, demographic history, or multigenerational stepping-stone dispersal. These findings bring out important spatial scale considerations to account for in the design of a protected area network that would efficiently enhance protection and persistence capacity of marine species. Mots-Clés: caribbean reef fish; connectivity; divergent selection; ecological data; ecological genetics; landscape genetics; marine connectivity; marine fish; Mediterranean Sea; Mullus surmuletus; neighbor matrices; oceanography; population-structure; sea; seascape genetics; single nucleotide polymorphism; surmuletus Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Dalongeville, A., et al. "Combining six genome scan methods to detect candidate genes to salinity in the Mediterranean striped red mullet (Mullus surmuletus)." BMC Genomics. 19 (2018): 217. Résumé: Background: Adaptive genomics may help predicting how a species will respond to future environmental changes. Genomic signatures of local adaptation in marine organisms are often driven by environmental selective agents impacting the physiology of organisms. With one of the highest salinity level, the Mediterranean Sea provides an excellent model to investigate adaptive genomic divergence underlying salinity adaptation. In the present study, we combined six genome scan methods to detect potential genomic signal of selection in the striped red mullet (Mullus surmuletus) populations distributed across a wide salinity gradient. We then blasted these outlier sequences on published fish genomic resources in order to identify relevant potential candidate genes for salinity adaptation in this species. Results: Altogether, the six genome scan methods found 173 outliers out of 1153 SNPs. Using a blast approach, we discovered four candidate SNPs belonging to three genes potentially implicated in adaptation of M. surmuletus to salinity. The allele frequency at one of these SNPs significantly increases with salinity independently from the effect of longitude. The gene associated to this SNP, SOCS2, encodes for an inhibitor of cytokine and has previously been shown to be expressed under osmotic pressure in other marine organisms. Additionally, our results showed that genome scan methods not correcting for spatial structure can still be an efficient strategy to detect potential footprints of selection, when the spatial and environmental variation are confounded, and then, correcting for spatial structure in a second step represents a conservative method. Conclusion: The present outcomes bring evidences of potential genomic footprint of selection, which suggest an adaptive response of M. surmuletus to salinity conditions in the Mediterranean Sea. Additional genomic data such as sequencing of a full-genome and transcriptome analyses of gene expression would provide new insights regarding the possibility that some striped red mullet populations are locally adapted to their saline environment. Mots-Clés: Adaptive genomics; Candidate genes; climate; genetics; Genome scan; landscape genomics; local adaptation; Mediterranean Sea; methionine sulfoxide reductase; Mullus surmuletus; population genomics; principal component analysis; r package; Salinity; selection; threespine sticklebacks Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Schmidt, N., et al. "Occurrence of microplastics in surface waters of the Gulf of Lion (NW Mediterranean Sea)." Progress in Oceanography. 163 (2018): 214–220. Résumé: Between 2014 and 2016 a total of 43 microplastic samples were collected at six sampling stations in the eastern section of the Gulf of Lion (located in the northwestern Mediterranean Sea), as well as upstream of the Rhône River. Microplastics were found in every sample with highly variable concentrations and masses. Concentrations ranged from 6 · 103 items km−2 to 1 · 106 items km−2 (with an average of 112 · 103 items km−2), and mass ranged from 0.30 g km−2 to 1018 g km−2 DW (mean 61.92 ± 178.03 g km−2). The samples with the highest and lowest microplastic count originate both from the Bay of Marseille. For the Bay of Marseille, it is estimated that the total microplastic load consist of 519 · 103 –101 · 106 items weighing 0.07–118 kg. Estimations for daily microplastic transport by the Northern Current and the Rhône River, two important hydrologic features of the northwestern Mediterranean Sea, range from 0.18 to 86.46 t and from 0.20 to 21.32 kg, respectively. Particles < 1 mm2 clearly dominated sampling stations in the Northern Current, the Rhône River and its plume (52, 53 and 61%, respectively), suggesting a long exposure time in the environment. Items between 1 mm2 and 5 mm2 in size were the most abundant microplastics in Marseille Bay (55%), which suggests coastal pollution sources or the removal of smaller particles from surface waters e.g. by ballasting owing to the presence of epibionts. Mots-Clés: Gulf of Lion; Marine litter; Marseille Bay; Mediterranean Sea; Microplastic Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Zupan, M., et al. "How good is your marine protected area at curbing threats?" Biol. Conserv.. 221 (2018): 237–245. Résumé: Marine protected areas (MPAs) are key tools to mitigate human impacts in coastal environments, promoting sustainable activities to conserve biodiversity. The designation of MPAs alone may not result in the lessening of some human threats, which is highly dependent on management goals and the related specific regulations that are adopted. Here, we develop and operationalize a local threat assessment framework. We develop indices to quantify the effectiveness of MPAs (or individual zones within MPAs in the case of multiple-use MPAs) in reducing anthropogenic extractive and non-extractive threats operating at local scale, focusing specifically on threats that can be managed through MPAs. We apply this framework in 15 Mediterranean MPAs to assess their threat reduction capacity. We show that fully protected areas effectively eliminate extractive activities, whereas the intensity of artisanal and recreational fishing within partially protected areas, paradoxically, is higher than that found outside MPAs, questioning their ability at reaching conservation targets. In addition, both fully and partially protected areas attract non-extractive activities that are potential threats. Overall, only three of the 15 MPAs had lower intensities for the entire set of eight threats considered, in respect to adjacent control unprotected areas. Understanding the intensity and occurrence of human threats operating at the local scale inside and around MPAs is important for assessing MPAs effectiveness in achieving the goals they have been designed for, informing management strategies, and prioritizing specific actions. Mots-Clés: conservation; coral-reefs; dangerous targets; Extractive activities; fisheries; Fully protected area; management; Management; Marine use; mediterranean sea; mpa; Non-extractive activities; Partially protected area; reserves; science; spillover Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML 2017 Albo-Puigserver, M., et al. "Ecological energetics of forage fish from the Mediterranean Sea: Seasonal dynamics and interspecific differences." Deep-Sea Res. Part II-Top. Stud. Oceanogr.. 140 (2017): 74–82. Résumé: Small and medium pelagic fishes play a central role in marine food webs by transferring energy from plankton to top predators. In this study, direct calorimetry was used to analyze the energy density of seven pelagic species collected over four seasons from the western Mediterranean Sea: anchovy Engraulis encrasicolus, sardine Sardina pilchardus, round sardinella Sardinella aurita, horse mackerels Trachurus trachurus and T. mediterraneus, and mackerels Scomber scombrus and S. colias. Inter-specific differences in energy density were linked to spawning period, energy allocation strategies for reproduction and growth, and feeding ecologies. Energy density of each species varied over time, with the exception of S. colitis, likely due to its high energetic requirements related to migration throughout the year. In general, higher energy density was observed in spring for all species, regardless of their breeding strategy, probably as a consequence of the late-winter phytoplankton bloom. These results provide new insights into the temporal availability of energy in the pelagic ecosystem of the Mediterranean Sea, which are pivotal for understanding how the population dynamics of small and medium pelagic fishes and their predators may respond to environmental changes and fishing impacts. In addition, the differences found in energy density between species highlighted the importance of using species specific energy values in ecosystem assessment tools such as bioenergetic and food web models. Mots-Clés: anchovy engraulis-encrasicolus; Bioenergetics; climate-change; diet composition; Energy density; environmental variability; feeding-habits; food webs; horse mackerel; Mediterranean Sea; north aegean sea; osteichthyes carangidae; sardine sardina-pilchardus; small pelagic fish Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Arnaud-Haond, S., et al. "Entangled fates of holobiont genomes during invasion: nested bacterial and host diversities in Caulerpa taxifolia." Mol. Ecol.. 26.8 (2017): 2379–2391. Résumé: Successful prevention and mitigation of biological invasions requires retracing the initial steps of introduction, as well as understanding key elements enhancing the adaptability of invasive species. We studied the genetic diversity of the green alga Caulerpa taxifolia and its associated bacterial communities in several areas around the world. The striking congruence of alpha and beta diversity of the algal genome and endophytic communities reveals a tight association, supporting the holobiont concept as best describing the unit of spreading and invasion. Both genomic compartments support the hypotheses of a unique accidental introduction in the Mediterranean and of multiple invasion events in southern Australia. In addition to helping with tracing the origin of invasion, bacterial communities exhibit metabolic functions that can potentially enhance adaptability and competitiveness of the consortium they form with their host. We thus hypothesize that low genetic diversities of both host and symbiont communities may contribute to the recent regression in the Mediterranean, in contrast with the persistence of highly diverse assemblages in southern Australia. This study supports the importance of scaling up from the host to the holobiont for a comprehensive understanding of invasions. Mots-Clés: Algae; australia; Caulerpa; Chlorophyta; clonal diversity; dna; endophytic communities; genetic diversity; holobiont; invasion paradox; marine invasion; Mediterranean Sea; microsatellite markers; parasites; plant invasions; polymorphism Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Arnaud-Haond, S., et al. "Two "pillars" of cold-water coral reefs along Atlantic European margins: Prevalent association of Madrepora oculata with Lophelia pertusa, from reef to colony scale." Deep-Sea Res. Part II-Top. Stud. Oceanogr.. 145 (2017): 110–119. Résumé: The scleractinian coral Lophelia pertusa has been the focus of deep-sea research since the recognition of the vast extent of coral reefs in North Atlantic waters two decades ago, long after their existence was mentioned by fishermen. These reefs where shown to provide habitat, concentrate biomass and act as feeding or nursery grounds for many species, including those targeted by commercial fisheries. Thus, the attention given to this cold-water coral (CWC) species from researchers and the wider public has increased. Consequently, new research programs triggered research to determine the full extent of the corals geographic distribution and ecological dynamics of "Lophelia reefs". The present study is based on a systematic standardised sampling design to analyze the distribution and coverage of CWC reefs along European margins from the Bay of Biscay to Iceland. Based on Remotely Operated Vehicle (ROV) image analysis, we report an almost systematic occurrence of Madrepora oculata in association with L. pertusa with similar abundances of both species within explored reefs, despite a tendency of increased abundance of L. pertusa compared to M. oculata toward higher latitudes. This systematic association occasionally reached the colony scale, with "twin" colonies of both species often observed growing next to each other when isolated structures were occurring offireefs. Finally, several "false chimaera" were observed within reefs, confirming that colonial structures can be "coral bushes" formed by an accumulation of multiple colonies even at the inter-specific scale, with no need for self-recognition mechanisms. Thus, we underline the importance of the hitherto underexplored M. oculata in the Eastern Atlantic, reestablishing a more balanced view that both species and their yet unknown interactions are required to better elucidate the ecology, dynamics and fate of European CWC reefs in a changing environment. Mots-Clés: community; bay; Bay of Biscay; Lophelia pertusa; Madrepora oculata; biscay; mediterranean sea; Cold water corals (CWC); deep-sea corals; False-chimaera colonies; fleuve manche; hydrodynamics; Iceland; Ireland; megafauna; mid-norway; ne atlantic Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Authier, M., C. Saraux, and C. Péron. "Variable selection and accurate predictions in habitat modelling: a shrinkage approach." Ecography. 40.4 (2017): 549–560. Résumé: Habitat modelling is increasingly relevant in biodiversity and conservation studies. A typical application is to predict potential zones of specific conservation interest. With many environmental covariates, a large number of models can he investigated but multi-model inference may become impractical. Shrinkage regression overcomes this issue by dealing with the identification and accurate estimation of effect size for prediction. In a Bayesian framework we investigated the use of a shrinkage prior, the Horseshoe, for variable selection in spatial generalized linear models (GLM). As study cases, we considered 5 datasets on small pelagic fish abundance in the Gulf of Lion (Mediterranean Sea, France) and 9 environmental inputs. We compared the predictive performances of a simple kriging model, a full spatial GLM model with independent normal priors for regression coefficients, a full spatial GLM model with a Horseshoe prior for regression coefficients and 2 zero-inflated models (spatial and non-spatial) with a Horseshoe prior. Predictive performances were evaluated by cross validation on a hold-out subset of the data: models with a Horseshoe prior performed best, and the full model with independent normal priors worst. With an increasing number of inputs, extrapolation quickly became pervasive as we tried to predict from novel combinations of covariate values. By shrinking regression coefficients with a Horseshoe prior, only one model needed to be fitted to the data in order to obtain reasonable and accurate predictions, including extrapolations. Mots-Clés: account; distributional data; Ecology; indian-ocean; inference; Mediterranean Sea; regression methods; small pelagic fish; spatial autocorrelation; species distribution models Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Blanchet, M., et al. "When riverine dissolved organic matter (DOM) meets labile DOM in coastal waters: changes in bacterial community activity and composition." Aquat. Sci.. 79.1 (2017): 27–43. Résumé: Heterotrophic bacterial communities in marine environments are exposed to a heterogeneous mixture of dissolved organic compounds with different bioreactivity that may control both their activity and composition. The coastal environment is an example of a mixing area where recalcitrant allochthonous organic matter from rivers can encounter labile organic matter from marine phytoplanktonic blooms. The objective of this study was to explore the effects of mixed qualities of dissolved organic matter (DOM) on bacterial community activity (BCA) and bacterial community composition (BCC) and to test for a priming effect when DOM sources are added in combination. Coastal marine bacterial communities were incubated separately with a mixture of amino acids and with natural riverine DOM or with both sources together for 42 days. Addition of amino acids alone or in combination with riverine DOM led to a similar stimulation of BCA compared to control condition, whereas addition of riverine DOM alone did not modify BCA compared to the control. On the contrary, BCC analyzed by 16S rRNA gene pyrosequencing was not affected by the addition of amino acids alone, but changed dramatically with riverine DOM alone or in combination with amino acids. Our results show that changes in BCA and BCC can be driven by different types of DOM, but that these changes are not necessarily coupled. Moreover, the addition of labile DOM did not modify the microbial decomposition of riverine DOM, nor the BCC, suggesting that a priming effect did not occur under these experimental conditions. Mots-Clés: Bacterial community composition; bacterioplankton; biodegradation; carbon; coastal waters; Dissolved organic matter; Fluorescence; growth efficiency; lake water; marine; Mediterranean Sea; open-ocean; Priming effect; rhone river; terrestrial Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Bodin, N., et al. "Trace elements in oceanic pelagic communities in the western Indian Ocean." Chemosphere. 174 (2017): 354–362. Résumé: The mineral composition of target and non-target pelagic fish caught by purse-seiners and longliners in the western-central Indian Ocean was determined. From the 10 essential elements analysed, selenium and zinc showed the highest concentrations in swordfish and blue marlin while Indian mackerel appeared as a good source of copper, iron and chrome. All catch had levels of lead and cadmium, two toxic elements, below the maximum sanitary limits. Although some concerns were raised regarding mercury concentrations in the largest species (wahoo, swordfish and blue marlin), molar ratios of mercury and selenium indicate that all oceanic pelagic fish from the western-central Indian Ocean are safe for human consumption. This study also gives insights on the relationships between the levels of essential and toxic elements in fish muscle and the size, trophic position and diet sources of the studied pelagic species. (C) 2017 Elsevier Ltd. All rights reserved. Mots-Clés: atlantic-ocean; blue marlin; Environmental risk assessment; makaira-nigricans; Marine fish; Mediterranean Sea; Mercury; mercury content; North Pacific; risk-assessment; Seafood; Selenium; swordfish xiphias-gladius; Tuna fisheries' bycatch Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Cahill, A. E., et al. "A multispecies approach reveals hot spots and cold spots of diversity and connectivity in invertebrate species with contrasting dispersal modes." Mol. Ecol.. 26.23 (2017): 6563–6577. Résumé: Genetic diversity is crucial for species' maintenance and persistence, yet is often overlooked in conservation studies. Species diversity is more often reported due to practical constraints, but it is unknown if these measures of diversity are correlated. In marine invertebrates, adults are often sessile or sedentary and populations exchange genes via dispersal of gametes and larvae. Species with a larval period are expected to have more connected populations than those without larval dispersal. We assessed the relationship between measures of species and genetic diversity, and between dispersal ability and connectivity. We compiled data on genetic patterns and life history traits in nine species across five phyla. Sampling sites spanned 600km in the northwest Mediterranean Sea and focused on a 50-km area near Marseilles, France. Comparative population genetic approaches yielded three main results. (i) Species without larvae showed higher levels of genetic structure than species with free-living larvae, but the role of larval type (lecithotrophic or planktotrophic) was negligible. (ii) A narrow area around Marseilles, subject to offshore advection, limited genetic connectivity in most species. (iii) We identified sites with significant positive contributions to overall genetic diversity across all species, corresponding with areas near low human population densities. In contrast, high levels of human activity corresponded with a negative contribution to overall genetic diversity. Genetic diversity within species was positively and significantly linearly related to local species diversity. Our study suggests that local contribution to overall genetic diversity should be taken into account for future conservation strategies. Mots-Clés: genetic diversity; dispersal; life-history traits; reef fishes; marine connectivity; pelagic larval duration; mediterranean sea; amphipholis-squamata; brooding brittle star; coralligenous assemblages; larvae; marine invertebrates; phylogeographical breaks; population structure; population genetic-structure; species genetic diversity correlation Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Coll, M., and J. Steenbeek. "Standardized ecological indicators to assess aquatic food webs: The ECOIND software plug-in for Ecopath with Ecosim models." Environ. Modell. Softw.. 89 (2017): 120–130. Résumé: Ecological indicators are useful tools to analyse and communicate historical changes in ecosystems and plausible future scenarios while evaluating environmental status. Here we introduce a new plug-in to the Ecopath with Ecosim (EwE) food web modelling approach, which is widely used to quantitatively describe aquatic ecosystems. The plug-in (ECOIND) calculates standardized ecological indicators. We describe the primary functionality of ECOIND and provide an example of its application in both static and temporal-spatial dynamic modelling, while we highlight several related features including a new taxonomy input database (species traits) and the ability to analyse input uncertainty on output results. ECOIND adds new capabilities to the widely used EwE food web modelling approach and enables broadening its applications into biodiversity and conservation-based frameworks to contribute to integrated ecosystem analyses. (C) 2016 Elsevier Ltd. All rights reserved. Mots-Clés: biodiversity; Conservation; Ecological standardized indicators; Ecopath with Ecosim; ecospace; Ecosystem indicators; Environmental status; Fisheries management; Food web models; impacts; index; marine ecosystems; Mediterranean Sea; network analysis; ocean; Software plug-in Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Pennino, M. G., et al. "The analysis of convergence in ecological indicators: An application to the Mediterranean fisheries." Ecological Indicators. 78.Supplement C (2017): 449–457. Résumé: Ecological indicators are increasingly used to examine the evolution of natural ecosystems and the impacts of human activities. Assessing their trends to develop comparative analyses is essential. We introduce the analysis of convergence, a novel approach to evaluate the dynamic and trends of ecological indicators and predict their behavior in the long-term. Specifically, we use a non-parametric estimation of Gaussian kernel density functions and transition probability matrix integrated in the R software. We validate the performance of our methodology through a practical application to three different ecological indicators to study whether Mediterranean countries converge towards similar fisheries practices. We focus on how distributions evolve over time for the Marine Trophic Index, the Fishing in Balance Index and the Expansion Factor during 1950–2010. Results show that Mediterranean countries persist in their fishery behaviors throughout the time series, although a tendency towards similar negative effects on the ecosystem is apparent in the long-term. This methodology can be easily reproduced with different indicators and/or ecosystems in order to analyze ecosystem dynamics. Mots-Clés: Convergence analysis; ecological indicators; Ecosystem Approach to Fisheries Management; Mediterranean Sea; Non-parametric density estimation; Transition probability matrix Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML 2016 Ben-Gharbia, H., et al. "Toxicity and Growth Assessments of Three Thermophilic Benthic Dinoflagellates (Ostreopsis cf. ovata, Prorocentrum lima and Coolia monotis) Developing in the Southern Mediterranean Basin." Toxins. 8.10 (2016): 297. Résumé: Harmful benthic dinoflagellates, usually developing in tropical areas, are expanding to temperate ecosystems facing water warming. Reports on harmful benthic species are particularly scarce in the Southern Mediterranean Sea. For the first time, three thermophilic benthic dinoflagellates (Ostreopsis cf. ovata, Prorocentrum lima and Coolia monotis) were isolated from Bizerte Bay (Tunisia, Mediterranean) and monoclonal cultures established. The ribotyping confirmed the morphological identification of the three species. Maximum growth rates were 0.59 +/- 0.08 d(-1) for O. cf. ovata, 0.35 +/- 0.01 d(-1) for C. monotis and 0.33 +/- 0.04 d(-1) for P. lima. Toxin analyses revealed the presence of ovatoxin-a and ovatoxin-b in O. cf. ovata cells. Okadaic acid and dinophysistoxin-1 were detected in P. lima cultures. For C. monotis, a chromatographic peak at 5.6 min with a mass m/z = 1061.768 was observed, but did not correspond to a mono-sulfated analogue of the yessotoxin. A comparison of the toxicity and growth characteristics of these dinoflagellates, distributed worldwide, is proposed. Mots-Clés: coastal waters; Coolia monotis; environmental-factors; growth; gulf-of-california; harmful algal blooms; marine dinoflagellate; multiple sequence alignment; new-zealand; okadaic acid; Ostreopsis cf. ovata; Prorocentrum lima; Southern Mediterranean Sea; sp-nov dinophyceae; toxicity; toxin profile Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Brophy, D., et al. "Otolith shape variation provides a marker of stock origin for north Atlantic bluefin tuna (Thunnus thynnus)." Mar. Freshw. Res.. 67.7 (2016): 1023–1036. Résumé: Two stocks of bluefin tuna (Thunnus thynnus) inhabit the north Atlantic; the western and eastern stocks spawn in the Gulf of Mexico and the Mediterranean Sea respectively. Trans-Atlantic movements occur outside spawning time whereas natal homing maintains stock structure. Commercial fisheries may exploit a mixed assemblage of both stocks. The incorporation of mixing rates into stock assessment is precluded by uncertainties surrounding stock discrimination. Otolith shape descriptors were used to characterise western and eastern stocks of Atlantic bluefin tuna in the present study and to estimate stock composition in catches of unknown origin. Otolith shape varied with length and between locations and years. Within a restricted size range (200-297-cm fork length (FL)) the two stocks were distinguished with an accuracy of 83%. Bayesian stock mixture analysis indicated that samples from the east Atlantic and Mediterranean were predominantly of eastern origin. The proportion assigned to the eastern stock showed slight spatial variation; however, overlapping 95% credible intervals indicated no significant difference (200-297 cm FL: central Atlantic, 73-100%; Straits of Gibraltar, 73-100%; Morocco, 50-99%; Portugal 64-100%). Otolith shape could be used in combination with other population markers to improve the accuracy of mixing rate estimates for Atlantic bluefin tuna. Mots-Clés: carrying-capacity; elliptical Fourier analysis; fish; holistic approach; identification; management; Mediterranean Sea; mitochondrial-dna; population structure; population-structure; spatial structure; stock mixture analysis; western atlantic Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Brosset, P., et al. "Linking small pelagic dietary shifts with ecosystem changes in the Gulf of Lions." Mar. Ecol.-Prog. Ser.. 554 (2016): 157–171. Résumé: Since 2008, a severe decrease in size and body condition together with a demographic truncation has been observed in the sardine (secondarily in anchovy) population of the Gulf of Lions (NW Mediterranean Sea). In parallel, sprat biomass, which was negligible before, has increased tenfold. All of these changes have strongly affected the regional fisheries. Using trophic and isotopic data from contrasting periods of low versus high growth and condition, we investigated potential changes in diet and interspecific feeding interactions through time. Evidence of resource partitioning was found between sprat and both anchovy and sardine in 2004 and 2005. Since 2010, the isotopic niches of the 3 species have tended to overlap, suggesting higher risk of competition for food resources. Moreover, the wider trophic niche of sprat indicates higher variability in individual diets. Anchovy and sardine diet varied through time, with a high proportion of large copepods or cladocerans in periods of high growth and condition (1994 and 2007, respectively) versus a dominance of small copepods in the present (2011-2012). Furthermore, an important reduction in prey diversity was also identified in the diet of both anchovy and sardine during the most recent period. Our results support the hypothesis that changes in small pelagic fish growth, size and body condition and ultimately biomass could be due to bottom-up control characterized by changes in food availability and increasing potential trophic competition. Mots-Clés: anchovy; anchovy engraulis-encrasicolus; climate; Dietary overlap; fish; food-web; NW Mediterranean; nw mediterranean sea; plankton; regime shifts; Sardine; size-fractionated zooplankton; southern benguela; Sprat; stable-isotope ratios; Trophic ecology Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Dalongeville, A., et al. "Ecological traits shape genetic diversity patterns across the Mediterranean Sea: a quantitative review on fishes." J. Biogeogr.. 43.4 (2016): 845–857. Résumé: AimWe set out to identify the determinants of the variation in genetic diversity among fish species and test whether multi-species genetic diversity is randomly distributed in space. LocationMediterranean Sea. MethodsWe collected genetic diversity data from 39 published studies on Mediterranean fishes (31 species) along with the spatial coordinates of the sampling sites. We focused on microsatellite heterozygosity (151 data points) and mitochondrial haplotype diversity (201 data points). We used linear regressions to link genetic diversity and 11 ecological traits. We also tested for spatial autocorrelation and trends in the residuals. ResultsAmong-species variation in microsatellite heterozygosity was explained by three ecological traits: vertical distribution, migration type and body length. Variation in mitochondrial haplotype diversity was also explained by vertical distribution and migration type, and by reproductive strategy (semelparity). However, vertical distribution and migration type showed opposite effects on microsatellites and mitochondrial diversity. After accounting for the effects of ecological traits, no spatial pattern was detected, except for one of the species considered. Main conclusionsEcological factors explain an important proportion of the among-species genetic diversity. These results suggest that life history strategies of the species influence the variation of microsatellite diversity indirectly through their effect on effective population size, while the spatial variations of genetic diversity seem to be too complex to be identified in our analysis. We found very different effects of traits on mitochondrial and nuclear DNA diversity, which can be explained by the specificities of mitochondrial DNA (absence of recombination, maternal inheritance and non-neutrality). Mots-Clés: atlantic bluefin tuna; bass dicentrarchus-labrax; climate-change; cod gadus-morhua; ecological traits; effective population-size; genetic diversity; gilthead sea; life-history traits; marine fishes; marine populations; Mediterranean Sea; microsatellite markers; microsatellites; mitochondrial; mitochondrial DNA; molecular markers; population genetics Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Druon, J. - N., et al. "Habitat suitability of the Atlantic bluefin tuna by size class: An ecological niche approach." Progress in Oceanography. 142 (2016): 30–46. Résumé: An ecological niche modelling (ENM) approach was used to predict the potential feeding and spawning habitats of small (5-25kg, only feeding) and large (> 25kg) Atlantic bluefin tuna (ABFT), Thunnus thynnus, in the Mediterranean Sea, the North Atlantic and the Gulf of Mexico. The ENM was built bridging knowledge on ecological traits of ABFT (e.g. temperature tolerance, mobility, feeding and spawning strategy) with patterns of selected environmental variables (chlorophyll-a fronts and concentration, sea surface current and temperature, sea surface height anomaly) that were identified using an extensive set of precisely geo-located presence data. The results highlight a wider temperature tolerance for larger fish allowing them to feed in the northern – high chlorophyll levels – latitudes up to the Norwegian Sea in the eastern Atlantic and to the Gulf of Saint Lawrence in the western basin. Permanent suitable feeding habitat for small ABFT was predicted to be mostly located in temperate latitudes in the North Atlantic and in the Mediterranean Sea, as well as in subtropical waters off north-west Africa, while summer potential habitat in the Gulf of Mexico was found to be unsuitable for both small and large ABFTs. Potential spawning grounds were found to occur in the Gulf of Mexico from March-April in the south-east to April-May in the north, while favourable conditions evolve in the Mediterranean Sea from mid-May in the eastern to mid-July in the western basin. Other secondary potential spawning grounds not supported by observations were predicted in the Azores area and off Morocco to Senegal during July and August when extrapolating the model settings from the Gulf of Mexico into the North Atlantic. The presence of large ABFT off Florida and the Bahamas in spring was not explained by the model as is, however the environmental variables other than the sea surface height anomaly appeared to be favourable for spawning in part of this area. Defining key spatial and temporal habitats should further help in building spatially-explicit stock assessment models, thus improving the spatial management of bluefin tuna fisheries. Mots-Clés: ecological niche; Environmental conditions; Feeding; Gulf of Mexico; habitat; Mediterranean sea; North Atlantic; Spawning; Thunnus thynnus Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Dubois, M., et al. "Linking basin-scale connectivity, oceanography and population dynamics for the conservation and management of marine ecosystems." Glob. Ecol. Biogeogr.. 25.5 (2016): 503–515. Résumé: AimAssessing the spatial structure and dynamics of marine populations is still a major challenge in ecology. The need to manage marine resources from ecosystem and large-scale perspectives is recognized, but our partial understanding of oceanic connectivity limits the implementation of globally pertinent conservation planning. Based on a biophysical model for the entire Mediterranean Sea, this study takes an ecosystem approach to connectivity and provides a systematic characterization of broad-scale larval dispersal patterns. It builds on our knowledge of population dynamics and discusses the ecological and management implications. LocationThe semi-enclosed Mediterranean Sea and its marine ecosystems are used as a case study to investigate broad-scale connectivity patterns and to relate them to oceanography and population dynamics. MethodsA flow network is constructed by evenly subdividing the basin into sub-regions which are interconnected through the transport of larvae by ocean currents. It allows for the computation of various connectivity metrics required to evaluate larval retention and exchange. ResultsOur basin-scale model predicts that retention processes are weak in the open ocean while they are significant in the coastal ocean and are favoured along certain coastlines due to specific oceanographic features. Moreover, we show that wind-driven divergent (convergent, respectively) oceanic regions are systematically characterized by larval sources (sinks, respectively). Finally, although these connectivity metrics have often been studied separately in the literature, we demonstrate they are interrelated under particular conditions. Their integrated analysis facilitates the appraisal of population dynamics, informing both genetic and demographic connectivities. Main conclusionsThis modelling framework helps ecologists and geneticists to formulate improved hypotheses of population structures and gene flow patterns and to design their sampling strategy accordingly. It is also useful in the implementation and assessment of future protection strategies, such as coastal and offshore marine reserves, by accounting for large-scale dispersal patterns, a missing component of current ecosystem management. Mots-Clés: coral-reef fish; dispersal; genetic-structure; Larval dispersal; local retention; local retention; marine connectivity; marine ecosystems; marine protected areas; mediterranean littoral fishes; Mediterranean Sea; metapopulation; pelagic larval duration; population dynamics; Population Genetics; protected-area design; sea; self-recruitment; sink dynamics; source Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Giakoumi, S., et al. "Space invaders; biological invasions in marine conservation planning." Divers. Distrib.. 22.12 (2016): 1220–1231. Résumé: AimBiological invasions are major contributors to global change and native biodiversity decline. However, they are overlooked in marine conservation plans. Here, we examine for the first time the extent to which marine conservation planning research has addressed (or ignored) biological invasions. Furthermore, we explore the change of spatial priorities in conservation plans when different approaches are used to incorporate the presence and impacts of invasive species. LocationGlobal analysis with a focus on the Mediterranean Sea region. MethodsWe conducted a systematic literature review consisting of three steps: (1) article selection using a search engine, (2) abstract screening and (3) review of pertinent articles, which were identified in the second step. The information extracted included the scale and geographical location of each case study as well as the approach followed regarding invasive species. We also applied the software Marxan to produce and compare conservation plans for the Mediterranean Sea that either protect, or avoid areas impacted by invasives, or ignore the issue. One case study focused on the protection of critical habitats, and the other on endemic fish species. ResultsWe found that of 119 papers on marine spatial plans in specific biogeographic regions, only three (2.5%) explicitly took into account invasive species. When comparing the different conservation plans for each case study, we found that the majority of selected sites for protection (ca. 80%) changed in the critical habitat case study, while this proportion was lower but substantial (27%) in the endemic fish species case study. Main conclusionsBiological invasions are being widely disregarded when planning for conservation in the marine environment across local to global scales. More explicit consideration of biological invasions can significantly alter spatial conservation priorities. Future conservation plans should explicitly account for biological invasions to optimize the selection of marine protected areas. Mots-Clés: alien species; biodiversity; biological invasions; coastal; conservation planning; cost; diversity; ecosystem; impacts; management actions; marine biogeographic regions; marine protected areas; Mediterranean Sea; pathways; protected areas; strategy Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Halouani, G., et al. "Modelling food web structure using an end-to-end approach in the coastal ecosystem of the Gulf of Gabes (Tunisia)." Ecological Modelling. 339 (2016): 45–57. Résumé: Given the ecological importance and high socio-economic value of the fishery of the Gulf of Gabes, an end-to-end model was applied to its continental shelf ecosystem to characterize the structure of the food web in the 2000s. This approach consisted in forcing a high trophic level model (OSMOSE) with an existing biogeochemical model (Eco3M-MED) representing the seasonal dynamics of the low trophic levels. The two models were linked through trophic interactions to represent the ecosystem dynamics from primary producers to top predators. In this study, we developed the multispecies, individual-based model OSMOSE in the Gulf of Gabes (OSMOSE-GoG). This model aims to capture the main processes that influence species life cycle and simulate the functioning of the ecosystem according to opportunistic predation process based on size selection and spatio-temporal co-occurrence between a predator and its prey. The spatial distribution of the eleven modelled species was derived from a Multi-Scale Species Distribution Modelling approach. We calibrated OSMOSE-GoG model with available data of biomass and fishing yield, using an optimization method based on evolutionary algorithms which is suitable for complex and stochastic models. Finally, OSMOSE-GoG was validated against independent data sets at different hierarchical levels: the individual (diet composition), population (mean size of commercial catch) and community levels (mean trophic level) following the Pattern-Oriented Modelling approach. The model outputs were overall consistent with the diet compositions and mean trophic levels derived from the ECOPATH model of the Gulf of Gabes (ECOPATH-GoG) and the observations of mean size of catches. The OSMOSE-GoG can be considered as a baseline model to investigate ecosystem responses to environmental changes and fishing management measures in the Gulf of Gabes. Mots-Clés: ecosystem model; End-to-end modelling; food web; Gulf of Gabes; Mediterranean Sea; Osmose Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Heymans, J. J., et al. "Best practice in Ecopath with Ecosim food-web models for ecosystem-based management." Ecol. Model.. 331 (2016): 173–184. Résumé: Ecopath with Ecosim (EwE) models are easier to construct and use compared to most other ecosystem modelling techniques and are therefore more widely used by more scientists and managers. This, however, creates a problem with quality assurance; to address this we provide an overview of best practices for creating Ecopath, models. We describe the diagnostics that can be used to check for thermodynamic and ecological principles, and highlight principles that should be used for balancing a model. We then highlight the pitfalls when comparing Ecopath models using Ecological Network Analysis indices. For dynamic simulations in Ecosim we show the state of the art in calibrating the model by fitting it to time series using a formal fitting procedure and statistical goodness of fit. Finally, we show how Monte Carlo simulations can be used to address uncertainty in input parameters, and we discuss the use of models in a management context, specifically using the concept of 'key runs' for ecosystem-based management. This novel list of best practices for EwE models will enable ecosystem managers to evaluate the goodness of fit of the given EwE model to the ecosystem management question. (C) 2016 The Authors. Published by Elsevier B.V. Mots-Clés: benguela ecosystem; dynamics; Ecological network analysis; Ecopath with Ecosim; Ecosystem-based management; Ecosystem modelling; exploited ecosystems; impacts; indicators; marine ecosystems; Monte Carlo; network analysis; nw mediterranean sea; shelf ecosystem; southern benguela; Time series fitting Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Meistertzheim, A. - L., et al. "Patterns of bacteria-host associations suggest different ecological strategies between two reef building cold-water coral species." Deep Sea Research Part I: Oceanographic Research Papers. 114 (2016): 12–22. Résumé: Cold-water corals (CWC) are main ecosystem engineers of the deep sea, and their reefs constitute hot-spots of biodiversity. However, their ecology remains poorly understood, particularly, the nature of the holobiont formed by corals with their associated bacterial communities. Here, we analyzed Madrepora oculata and Lophelia pertusa samples, collected from one location in a Mediterranean canyon in two different seasons (autumn and spring), in order to test for species specificity and temporal stability of the host-bacteria associations. The 16S rRNA sequencing revealed host-specific patterns of bacterial communities associated with L. pertusa and M. oculata, both in terms of community composition and diversity. All analyzed M. oculata polyps exhibited temporally and spatially similar bacterial communities dominated by haplotypes homologous to the known cnidarians-associated genus Endozoicomonas. In contrast, the bacterial communities associated with L. pertusa varied among polyps from the same colony, as well as among distinct colonies and between seasons. While the resilient consortium formed by M. oculata and its bacterial community fit the definition of holobiont, the versatility of the L. pertusa microbiome suggests that this association is more influenced by the environmental conditions or nutritional status. Our results thus highlight distinct host/microbes association strategies for these two closely related Scleractinians sharing the same habitat, suggesting distinct sensitivity to environmental change. Mots-Clés: Bacterial communities; Bacterial ecology; Deep-Sea corals; Lophelia pertusa; Madrepora oculata; Mediterranean Sea; Microbe-microbe and microbe-host interactions Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Navarro, J., et al. "Differences in the relative roles of environment, prey availability and human activity in the spatial distribution of two marine mesopredators living in highly exploited ecosystems." J. Biogeogr.. 43.3 (2016): 440–450. Résumé: Aim Identifying the main factors affecting the spatial distribution of marine predators is essential in order to evaluate their distribution patterns, predict the potential impact of human activities on their populations and design accurate management actions. This information is also valuable from a more general management perspective, as marine predators are often considered indicators of habitat quality. In this context, we aimed to determine the degree to which environmental features, prey availability and human activities interact and influence spatial distribution of two marine mesopredator elasmobranchs, the small-spotted catshark (Scyliorhinus canicula) and the Mediterranean starry ray (Raja asterias), living in a highly human-exploited environment. Location Mediterranean Sea. Methods With information obtained from an extended experimental survey, we investigated the relative importance of environmental variables, prey availability and human activities on the spatial distribution of the abundance, biomass and occurrence rate of these marine mesopredators using deviance partitioning analyses. Results Our results revealed that environmental variables were the most important factors explaining the spatial distribution of Mediterranean starry ray, whereas small-spotted catshark distribution was also influenced by prey availability and human factors. From a management point of view, these findings suggest that Mediterranean starry ray could be a good candidate as an indicator species of demersal environmental quality. On the other hand, the distribution of the small-spotted catshark, which responds in an interactive and complex way to environment, prey availability and particular human activities, may be misleading as an environmental indicator. Main conclusions The spatial distribution of elasmobranchs in highly human-impacted marine areas can reflect the interactive and combined effects of multiple factors. To avoid misunderstandings, attention should be paid to statistical procedures allowing the separation of pure and joint contribution of the factors driving the observed spatial patterns. Mots-Clés: deviance partitioning; elasmobranchs; environmental variables; human stressors; indicator species; marine biodiversity; Marine conservation; Mediterranean Sea; Raja asterias; Scyliorhinus canicula Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Sebastian, M., et al. "Lipid remodelling is a widespread strategy in marine heterotrophic bacteria upon phosphorus deficiency." Isme J.. 10.4 (2016): 968–978. Résumé: Upon phosphorus (P) deficiency, marine phytoplankton reduce their requirements for P by replacing membrane phospholipids with alternative non-phosphorus lipids. It was very recently demonstrated that a SAR11 isolate also shares this capability when phosphate starved in culture. Yet, the extent to which this process occurs in other marine heterotrophic bacteria and in the natural environment is unknown. Here, we demonstrate that the substitution of membrane phospholipids for a variety of non-phosphorus lipids is a conserved response to P deficiency among phylogenetically diverse marine heterotrophic bacteria, including members of the Alphaproteobacteria and Flavobacteria. By deletion mutagenesis and complementation in the model marine bacterium Phaeobacter sp. MED193 and heterologous expression in recombinant Escherichia coli, we confirm the roles of a phospholipase C (PlcP) and a glycosyltransferase in lipid remodelling. Analyses of the Global Ocean Sampling and Tara Oceans metagenome data sets demonstrate that PlcP is particularly abundant in areas characterized by low phosphate concentrations. Furthermore, we show that lipid remodelling occurs seasonally and responds to changing nutrient conditions in natural microbial communities from the Mediterranean Sea. Together, our results point to the key role of lipid substitution as an adaptive strategy enabling heterotrophic bacteria to thrive in the vast P-depleted areas of the ocean. Mots-Clés: 2 enzymes; agrobacterium-tumefaciens; bacterioplankton groups; Ecology; Mediterranean Sea; mesocosm experiment; microbial food-web; north-atlantic ocean; nutrient limitation; phosphate starvation Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Triki, H. Z., et al. "First report of goniodomin A production by the dinoflagellate Alexandrium pseudogonyaulax developing in southern Mediterranean (Bizerte Lagoon, Tunisia)." Toxicon. 111 (2016): 91–99. Résumé: The dinoflagellate Alexandrium pseudogonyaulax is widely distributed around the world including the Mediterranean waters. The objectives of this study were to determine the morphology and phylogenic affiliation of A. pseudogonyaulax strain isolated from Bizerte Lagoon (Mediterranean waters, Tunisia) and investigate its toxicity. Molecular analyses confirmed the morphological identification of the isolated strain (APBZ12) as A. pseudogonyaulax. Moreover, it showed that it is 100% identical with strains of this species found in New Zealand, Japan, China and North Sea (Norway and Denmark) suggesting that this species is cosmopolitan. Until now, no toxin studies have been conducted on fully characterized (morphologically and molecularly) A. pseudogonyaulax. Cellular toxin production was determined using high pressure liquid chromatography coupled to mass spectrometry (HPLC/MS). Results showed for the first time that A. pseudogonyaulax contains goniodomin A (GDA), a highly toxic macrolide polyether previously shown to be produced by two other dinoflagellate species Alexandrium monilatum (Hsia et al., 2006) and Alexandrium hiranoi (erroneously identified as A. pseudogonyaulax in Murakami et al., 1988) in American and Japanese waters, respectively. This biologically active toxin has been associated over decades with fish mortality. Our study showed that the cell extracts of APBZ12 showed an important bioactivity using GH4C1 rat pituitary cytotoxicity bioassay. Mots-Clés: Alexandrium pseudogonyaulax; goniodomin A; Mediterranean sea; morphology; Phylogeny Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML 2015 Albo-Puigserver, M., et al. "Feeding ecology and trophic position of three sympatric demersal chondrichthyans in the northwestern Mediterranean." Mar. Ecol.-Prog. Ser.. 524 (2015): 255–268. Résumé: Understanding how marine predators interact is a scientific challenge. In marine ecosystems, segregation in feeding habits has been largely described as a common mechanism to allow the coexistence of several competing marine predators. However, little is known about the feeding ecology of most species of chondrichthyans, which play a pivotal role in the structure of marine food webs worldwide. In this study, we examined the trophic ecology of 3 relatively abundant chondrichthyans coexisting in the Mediterranean Sea: the blackmouth catshark Galeus melastomus, the velvet belly lanternshark Etmopterus spinax and the rabbit fish Chimaera monstrosa. To examine their trophic ecology and interspecific differences in food habits, we combined the analysis of stomach content and stable isotopes. Our results highlighted a trophic segregation between C. monstrosa and the other 2 species. G. melastomus showed a diet composed mainly of cephalopods, while E. spinax preyed mainly on shrimps and C. monstrosa on crabs. Interspecific differences in the trophic niche were likely due to different feeding capabilities and body size. Each species showed different isotopic niche space and trophic level. Specifically, C. monstrosa showed a higher trophic level than E. spinax and G. melastomus. The high trophic levels of the 3 species highlighted their important role as predators in the marine food web. Our results illustrate the utility of using complementary approaches that provide information about the feeding behaviour at short (stomach content) and long-term scales (stable isotopes), which could allow more efficient monitoring of marine food-web changes in the study area. Mots-Clés: Chimaera monstrosa; chimera-monstrosa; discrimination factors; Etmopterus spinax; etmopterus-spinax linnaeus; Feeding niche; fishing impacts; food-web; Galeus melastomus; galeus-melastomus; interpreting stable-isotopes; Isotope analysis; Mediterranean Sea; portuguese continental-slope; sea; top predators Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Albouy, C., et al. "FishMed: traits, phylogeny, current and projected species distribution of Mediterranean fishes, and environmental data." Ecology. 96.8 (2015): 2312–2313. Résumé: The FishMed database provides traits, phylogeny, current and projected species distribution of Mediterranean fishes, and associated sea surface temperature (SST) from the regional oceanic model NEMOMED8. Data for the current geographical distributions of 635 Mediterranean fish species were compiled from a published expert knowledge atlas of fishes of the northern Atlantic and the Mediterranean (FNAM) edited between 1984 and 1986 and from an updated exotic fish species list. Two future sets of projected species distributions were obtained for the middle and end of the 21st century by using an ensemble forecasting approach for 288 coastal Mediterranean fish species based on SST according to the IPPC/SRES A2 scenario implemented with the Mediterranean climatic model NEMOMED8. The functional part of the database encompasses 12 biological and ecological traits (maximal and common lengths, vertical distribution, habitat, migration type, mode of reproduction, sex shift, semelparity, diet type (larvae and adults), social behavior, species origin, and depth) for the 635 fish species. To build the phylogeny we inferred the timing and geographic origins of Mediterranean teleost species diversity using nucleotide sequences collected from GenBank including 62% of Mediterranean teleost species plus nine outgroups. Maximum likelihood Bayesian phylogenetic and dating analyses were calibrated using 20 fossil species. An additional 124 fish species were grafted onto the chronogram according to their taxonomic affinity to obtain a phylogenetic tree including 498 species. Finally we also present the associated SST data for the observed period (1961–1980) and for the middle (2040–2059) and the end of the 21st century (2080–2099) obtained from NEMOMED8 according to the IPCC A2 scenario. The FishMed database might be of interest in the context of global anthropogenic changes as coastal Mediterranean ecosystems are currently recognized as one of the most impacted ecosystems on earth. Mots-Clés: climate change; coastal fishes; functional diversity; Mediterranean fish species; Mediterranean Sea; Nemomed8; phylogenetic diversity; species distribution models; taxonomic diversity Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML BROSSET, P., et al. "Measurement and analysis of small pelagic fish condition: A suitable method for rapid evaluation in the field." Journal Of Experimental Marine Biology And Ecology. 462 (2015): 90–97. Résumé: As condition is a key variable in population dynamics (especially for survival, growth and reproduction), the use of well-defined and accurate fish condition indices is capital. In particular, condition indices (morphometric, bioenergetic and biochemical) have never been compared and validated for the European anchovy Engraulis encrasicolus, the European pilchard Sardina pilchardus and the European sprat Sprattus sprattus. The accuracy of two indirect methods, the morphometric relative condition index Kn and the bioenergetics index determined with the Distell Fish Fatmeter was investigated by comparing with a direct measure of relative lipid content carried out with a thin layer chromatography-flame ionization detector. Estimations from the fatmeter correlated quite well with the relative lipid contents of all species, regardless of the reproductive period (R2 = 0.69 for anchovy, R2 = 0.75 for sprat and R2 = 0.48 for sardine). Kn correlated more poorly with relative lipid content (R2 = 0.22 for anchovy and R2 = 0.41 for sardine, ns for sprat), especially during the reproductive period, pointing out the difficulty for such an index to precisely reflect changes in fat allocation. During the reproductive period, changes in Kn could reflect other processes, such as changes in protein content. Therefore, these different types of commonly used indices do not reflect exactly the same type of energy stores. The high repeatability of the fatmeter was brought to light, so that only one measurement on each fish side may be necessary to evaluate the relative lipid content of a small pelagic fish. Finally, fatmeter measurements were not affected by freezing storage up to one month for anchovy (R2 = 0.66) and sardine (R2 = 0.90), making it possible to use frozen samples of both commercial and scientific survey. In contrast, the freezing storage for sprat should be avoided. Based on this study, the Fatmeter appears to be a suitable indirect method to assess condition and fat content of sardine and anchovy on a large number of individuals. Mots-Clés: Anchovy; Fatmeter; Lipids; Mediterranean Sea; Sardine; Sprat Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML BROSSET, P., et al. "Influence of environmental variability and age on the body condition of small pelagic fish in the Gulf of Lions." Marine Ecology Progress Series. 529 (2015): 219–231. Résumé: Endogenous and environmental variables are fundamental in explaining variations in fish condition. Based on more than 20 yr of fish weight and length data, relative condition indices were computed for anchovy and sardine caught in the Gulf of Lions. Classification and regression trees (CART) were used to identify endogenous factors affecting fish condition, and to group years of similar condition. Both species showed a similar annual cycle with condition being minimal in February and maximal in July. CART identified 3 groups of years where the fish populations generally showed poor, average and good condition and within which condition differed between age classes but not according to sex. In particular, during the period of poor condition (mostly recent years), sardines older than 1 yr appeared to be more strongly affected than younger individuals. Time-series were analyzed using generalized linear models (GLMs) to examine the effects of oceanographic abiotic (temperature, Western Mediterranean Oscillation [WeMO] and Rhone outflow) and biotic (chlorophyll a and 6 plankton classes) factors on fish condition. The selected models explained 48 and 35% of the variance of anchovy and sardine condition, respectively. Sardine condition was negatively related to temperature but positively related to the WeMO and mesozooplankton and diatom concentrations. A positive effect of mesozooplankton and Rhone runoff on anchovy condition was detected. The importance of increasing temperatures and reduced water mixing in the NW Mediterranean Sea, affecting planktonic productivity and thus fish condition by bottom-up control processes, was highlighted by these results. Changes in plankton quality, quantity and phenology could lead to insufficient or inadequate food supply for both species. Mots-Clés: Anchovy; Sardine; Relative condition factor; NW Mediterranean Sea; Endogenous effect; Environmental effect Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Coll, M., et al. "'Low-hanging fruit' for conservation of marine vertebrate species at risk in the Mediterranean Sea." Frontiers in Microbiology. 24.2 (2015): 226–239. Résumé: AimConservation priorities need to take the feasibility of protection measures into account. In times of economic pressure it is essential to identify the low-hanging fruit' for conservation: areas where human impacts are lower and biological diversity is still high, and thus conservation is more feasible. LocationWe used the Mediterranean large marine ecosystem (LME) as a case study to identify the overlapping areas of low threats and high diversity of vertebrate species at risk. MethodsThis LME is the first in the world to have a complete regional IUCN Red List assessment of the native marine fish. We augmented these data with distributions of marine mammals, marine turtles and seabirds at risk, and we calculated the spatial distributions of species at risk (IUCN densities). Using cumulative threats we identified priority areas for conservation of species at risk' (PACS), where IUCN diversities are high and threats are low. We assessed whether IUCN diversities and PACS were spatially congruent among taxa and we quantified whether PACS corresponded to current and proposed protected areas. ResultsIUCN densities and PACS were not highly correlated spatially among taxa. Continental shelves and deep-sea slopes of the Alboran Sea, western Mediterranean and Tunisian Plateau/Gulf of Sidra are identified as relevant for fish species at risk. The eastern side of the western Mediterranean and the Adriatic Sea are identified as most relevant for endemic fish, and shelf and open sea areas distributed through the LME are most important for marine mammals and turtles at risk, while specific locations of the western Mediterranean Sea and the Aegean and Levantine seas are highlighted for seabirds. Main conclusionsLarge parts of the areas of PACS fell outside current or proposed frameworks to be prioritized for conservation. PACS may be suitable candidates for contributing to the 10% protection target for the Mediterranean Sea by 2020. Mots-Clés: Conservation priorities; cumulative threats; IUCN diversities; marine biodiversity; Marine Protected Areas; Mediterranean Sea Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Corrales, X., et al. "Ecosystem structure and fishing impacts in the northwestern Mediterranean Sea using a food web model within a comparative approach." Journal of Marine Systems. 148 (2015): 183–199. Résumé: We developed an ecological model to characterize the structure and functioning of the marine continental shelf and slope area of the northwestern Mediterranean Sea, from Toulon to Cape La Nao (NWM model), in the early 2000s. The model included previously modeled areas in the NW Mediterranean (the Gulf of Lions and the Southern Catalan Sea) and expanded their ranges, covering 45,547 km2, with depths from 0 to 1000 m. The study area was chosen to specifically account for the connectivity between the areas and shared fish stocks and fleets. Input data were based on local scientific surveys and fishing statistics, published data on stomach content analyses, and the application of empirical equations to estimate consumption and production rates. The model was composed of 54 functional groups, from primary producers to top predators, and Spanish and French fishing fleets were considered. Results were analyzed using ecological indicators and compared with outputs from ecosystem models developed in the Mediterranean Sea and the Gulf of Cadiz prior to this study. Results showed that the main trophic flows were associated with detritus, phytoplankton, zooplankton and benthic invertebrates. Several high trophic level organisms (such as dolphins, benthopelagic cephalopods, large demersal fishes from the continental shelf, and other large pelagic fishes), and the herbivorous salema fish, were identified as keystone groups within the ecosystem. Results confirmed that fishing impact was high and widespread throughout the food web. The comparative approach highlighted that, despite productivity differences, the ecosystems shared common features in structure and functioning traits such as the important role of detritus, the dominance of the pelagic fraction in terms of flows and the importance of benthic–pelagic coupling. Mots-Clés: comparative approach; Ecopath model; ecosystem approach to fisheries; fishing impacts; Mass-balance model; Northwestern Mediterranean Sea Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Halouani, G., et al. "Fishing impact in Mediterranean ecosystems: an EcoTroph modeling approach." Journal of Marine Systems. 150 (2015): 22–33. Résumé: The EcoTroph modeling approach was applied to five Mediterranean marine ecosystems to characterize their food webs and investigate their responses to several simulated fishing scenarios. First, EcoTroph was used to synthesize the outputs of five pre-existing heterogeneous Ecopath models in a common framework, and thus to compare different ecosystems through their trophic spectra of biomass, catch, and fishing mortalities. This approach contributes to our understanding of ecosystem functioning, from both ecological and fisheries perspectives. Then, we assessed the sensitivity of each ecosystem to fishery, using EcoTroph simulations. For the five ecosystems considered, we simulated the effects of increasing or decreasing fishing mortalities on both the biomass and the catch per trophic class. Our results emphasize that the Mediterranean Sea is strongly affected by the depletion of high trophic level organisms. Results also show that fisheries impacts, at the trophic level scale, differ between ecosystems according to their trophic structure and exploitation patterns. A top-down compensation effect is observed in some simulations where a fishing-induced decrease in the biomass of predators impacts their prey, leading to an increase in the biomass at lower trophic levels. The results of this comparative analysis highlight that ecosystems where top-down controls are observed are less sensitive to variations in fishing mortality in terms of total ecosystem biomass. This suggests that the magnitude of top-down control present in a system can affect its stability. Mots-Clés: Ecosystem modeling; EcoTroph; Fishing impact; food web; Mediterranean Sea; Trophic levels; Trophic spectrum Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Hattab, T., et al. "A biogeographical regionalization of coastal Mediterranean fishes." Journal of Biogeography. 42.7 (2015): 1336–1348. Résumé: AimTo delineate the biogeographical regions of the continental shelf of the Mediterranean Sea based on the spatial distributions of coastal marine fishes and their evolutionary relationships, with a view to furthering our capacity to answer basic and applied biogeographical, ecological and evolutionary questions. LocationMediterranean Sea. MethodsWe used a dataset summarizing the occurrences of 203 coastal Mediterranean fishes (0.1 degrees resolution grid system) and a molecular phylogenetic tree to quantify both compositional and phylogenetic dissimilarity (or beta diversity) between cells. We then applied multivariate analyses to delineate biogeographical regions and to evaluate how they related to broad-scale environmental gradients. We also assessed the differences between the biogeographical regions identified using phylogenetic beta diversity versus those obtained using compositional beta diversity. ResultsThe bioregionalization schemes based on phylogenetic and compositional beta diversity identified broadly similar regions, each consisting of six distinct pools of coastal fishes. Clear separations between northern and southern regions were observed, as well as a disjunct between inshore and offshore areas. These beta diversity patterns were mainly related to a north-south gradient in sea-surface temperature and bathymetric constraints. Main conclusionsIncorporating phylogenetic information into the measurement of beta diversity did not offer further insights to the bioregionalization scheme based solely on compositional beta diversity. This suggests that evolutionary and historical processes played only a minor role in shaping the contemporary patterns of beta diversity in the Mediterranean coastal fish fauna. However, our results support the view that contemporary environmental conditions play a major role in determining the distribution of these species. Mots-Clés: Beta diversity; Biogeography; bioregionalization; coastal fishes; compositional turnover; environmental gradient; historical processes; Mediterranean Sea; phylogenetic turnover; species composition Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Le Bourg, B., et al. "Trophic niche overlap of sprat and commercial small pelagic teleosts in the Gulf of Lions (NW Mediterranean Sea)." Journal of Sea Research (2015). Résumé: Increasing abundance of non-commercial sprats and decreasing biomass and landings of commercial anchovies and sardines justify the need to study the feeding ecology and trophic niche overlap of these planktivorous species in the Gulf of Lions. Their diet has been investigated on the basis of stomach content and stable isotope analyses in 2011 and 2012 according to different depths and regions in the study area. The main prey were Corycaeidae copepods, Clauso/Paracalanus, Euterpina acutifrons and Microsetella, for sprats and small copepods, such as Microsetella, Oncaea and Corycaeidae, for anchovies and sardines. This is the first time that the diet of sprats is described in the Gulf of Lions. Sprats fed on a larger size spectrum of prey and seem to be more generalist feeders compared to anchovies and sardines. Ontogenetic changes as well as spatial and temporal variations of the diet occurred in the three species. Stable isotope analysis revealed mobility of sardines and sprats among feeding areas while anchovies exhibited preferred feeding areas. Sprats showed a higher relative condition assessed by C/N ratios than sardines and anchovies. Our results showed an overlap of the trophic niches for the three species, indicating a potential trophic competition in the Gulf of Lions. Mots-Clés: Anchovies; Sardines; Sprats; North-western Mediterranean sea; Stomach contents; Stable isotopes Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Siddique, M. A. M., et al. "Fertilization strategies for Sea Bass Dicentrarchus labrax (Linnaeus, 1758): effects of pre-incubation and duration of egg receptivity in seawater." Aquac Res (2015): 1–9. Résumé: Studying gamete biology can provide important information about a species fertilization strategy as well as their reproductive ecology. Currently, there is a lack of knowledge about how long sea bass Dicentrarchus labrax eggs can remain viable after being activated in seawater. The objectives of this study were to understand the effects of pre-incubation of fresh and overripe sea bass eggs in seawater and to determine the duration of egg receptivity. Pooled eggs (fresh and overripe) from four females were pre-incubated in seawater for 0 min (control), 0.5 min, 1 min, 3 min, 10 min and 30 min and then fertilized by pooled sperm from four males. The fresh eggs had a higher fertilization success than overripe eggs. Our results revealed a significant effect of pre-incubation time for both the fresh (P < 0.01) and overripe eggs (P < 0.01). Fertilization success of eggs significantly declined for both these treatments after 3 min of pre-incubation, which clearly indicates that sea bass eggs are able to be fertilized by sperm for up to 3 min after release into seawater. This study has particular importance for understanding fertilization strategies, reproductive potential, as well as reproductive ecology of sea bass. Mots-Clés: Dicentrarchus labrax; egg longevity; Mediterranean sea bass; overripe eggs; reproductive ecology Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML 2014 Albouy, C., et al. "From projected species distribution to food-web structure under climate change." Global Change Biology. 20.3 (2014): 730–741. Mots-Clés: climate change; connectance; fish body size; food-webs; generality; Mediterranean Sea; metaweb; niche model; vulnerability Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Elleouet, J., et al. "A trait-based approach for assessing and mapping niche overlap between native and exotic species: the Mediterranean coastal fish fauna as a case study." Diversity and Distributions. 20.11 (2014): 1333–1344. Résumé: Aim We propose a trait-based approach for assessing and mapping potential niche overlap between native and exotic species at large spatial scales. Location The Mediterranean Sea. Methods We developed two complementary indices based on ecological, biological and ecomorphological similarities between native and exotic species. The first index (FNNr) allows identifying areas where native species are the most at risk in terms of potential ecological interactions with exotic species. The second index (FGO) is species-specific and allows identifying native species that display the broadest functional niche overlap and range overlap with exotic species. We illustrated our approach using the Mediterranean coastal fish fauna as a case study. Results We found that endemic and exotic fishes had a similar global functional niche at the Mediterranean scale, that is, they filled the same functional space defined by trait axes. FNNr hotspots were found to be moderately congruent with exotic species richness hotspots. Higher values of FNNr were observed along the coasts of the Levantine Sea. The computation of the FGO index showed that the geographical range of a given endemic species overlapped in average with 52 exotic species. Species showing the highest FGO values displayed localized and/or fragmented distributions in the eastern Mediterranean basin. Main conclusions Our findings suggest that the number of exotic species alone cannot be used as a broad-scale indicator of potential impact because this metric does not account for functional relatedness between native and exotic species. The trait-based indices developed in this study can be used for other taxa in both aquatic and terrestrial ecosystems and should help environmental managers to set up local-scale studies on areas where the potential impact of exotic species on native biodiversity is the highest. Mots-Clés: Biological invasions; coastal fishes; endemic species; exotic species; functional traits; Mediterranean Sea; niche overlap Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Hattab, T., et al. "Towards a better understanding of potential impacts of climate change on marine species distribution: a multiscale modelling approach." Global Ecology and Biogeography. 23.12 (2014): 1417–1429. Résumé: Aim In this paper, we applied the concept of 'hierarchical filters' in community ecology to model marine species distribution at nested spatial scales. Location Global, Mediterranean Sea and the Gulf of Gabes (Tunisia). Methods We combined the predictions of bioclimatic envelope models (BEMs) and habitat models to assess the current distribution of 20 exploited marine species in the Gulf of Gabes. BEMs were first built at a global extent to account for the full range of climatic conditions encountered by a given species. Habitat models were then built using fine-grained habitat variables at the scale of the Gulf of Gabes. We also used this hierarchical filtering approach to project the future distribution of these species under both climate change (the A2 scenario implemented with the Mediterranean climatic model NEMOMED8) and habitat loss (the loss of Posidonia oceanica meadows) scenarios. Results The hierarchical filtering approach predicted current species geographical ranges to be on average 56% smaller than those predicted using the BEMs alone. This pattern was also observed under the climate change scenario. Combining the habitat loss and climate change scenarios indicated that the magnitude of range shifts due to climate change was larger than from the loss of P. oceanica meadows. Main conclusions Our findings emphasize that BEMs may overestimate current and future ranges of marine species if species–habitat relationships are not also considered. A hierarchical filtering approach that accounts for fine-grained habitat variables limits the uncertainty associated with model-based recommendations, thus ensuring their outputs remain applicable within the context of marine resource management. Mots-Clés: climate change; exploited species; habitat loss; hierarchical filtering; Mediterranean Sea; spatial scale; species distribution modelling Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML 2013 Genovesi, B., et al. "Influences of sedimentation and hydrodynamics on the spatial distribution of Alexandrium catenella/tamarense resting cysts in a shellfish farming lagoon impacted by toxic blooms." Harmful Algae. 25 (2013): 15–25. Mots-Clés: Alexandrium; Hydrodynamics; Mapping; Resting cyst; Sediment; Spatial correlation; Thau Lagoon (Mediterranean Sea) Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML Giannoulaki, M., et al. "Characterizing the potential habitat of European anchovy Engraulis encrasicolus in the Mediterranean Sea, at different life stages." Fisheries Oceanography. 22.2 (2013): 69–89. Résumé: Identification of the potential habitat of European anchovy (Engraulis encrasicolus) at different life stages in relation to environmental conditions is an interesting subject from both ecological and management points of view. For this purpose, acoustic data from different seasons and different parts of the Mediterranean Sea along with satellite environmental and bathymetry data were modelled using generalized additive models. Similarly, egg distribution data from summer ichthyoplankton surveys were used to model potential spawning habitat. Selected models were used to produce maps presenting the probability of anchovy presence (adults, juveniles and eggs) in the entire Mediterranean basin, as a measure of habitat adequacy. Bottom depth and sea surface chlorophyll concentration were the variables found important in all models. Potential anchovy habitats were located over the continental shelf for all life stages examined. An expansion of the potential habitat from the peak spawning (early summer) to the late spawning season (early autumn) was observed. However, the most suitable areas for the presence of anchovy spawners seem to maintain the same size between seasons. Potential juvenile habitats were associated with highly productive inshore waters, being less extended and closer to coast during winter than late autumn. Potential spawning habitat in June and July based on ichthyoplankton surveys overlapped but were wider in extent compared with adult potential habitat from acoustics in the same season. Similarities and dissimilarities between the anchovy habitats as well as comparisons with sardine habitats in the oligotrophic Mediterranean Sea and other ecosystems with higher productivity are discussed. Mots-Clés: anchovy; anchovy potential nurseries; habitat suitability modelling; Mediterranean sea; small pelagics Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML PETHYBRIDGE, H., et al. "Responses of European anchovy vital rates and population growth to environmental fluctuations: An individual-based modeling approach." Ecological Modelling. 250 (2013): 370–383. Résumé: A size-structured, bioenergetics model was implemented to examine the effects of short-term environmental changes on European anchovy, Engraulis encrasicolus, in the North-western Mediterranean Sea. The model approach was based on Dynamic Energy Budget (DEB) theory and details the acquisition and allocation of energy (J d(-1)) during an organisms' full life-cycle. Model calibration was achieved using biometric data collected from the Gulf of Lions between 2002 and 2011. Bioenergetics simulations successfully captured ontogenetic and seasonal growth patterns, including active growth in spring/summer, loss of mass in autumn/winter and the timing and amplitude of multi-batch spawning events. Scenario analysis determined that vital rates (growth and fecundity) were highly sensitive to short-term environmental changes. The DEB model provided a robust foundation for the implementation of an individual-based population model (IBM) in which we used to test the responses of intrinsic and density-independent population growth rates (r) to observed and projected environmental variability. IBM projections estimate that r could be reduced by as much as 15% (relative to that estimated under mean conditions) due to either a 5% (0.8 degrees C) drop in temperature (due to a reduced spawning duration), a 18% (25 mg zooplankton m(-3)) depletion in food supply, a 30% increase in egg mortality rates, or with the phytoplankton bloom peaking 5 weeks earlier (in late-February/Winter). The sensitivity of r to short-term (1 year) and long-term (4-10 year) environmental changes were similar, highlighting the importance of first-year spawners. In its current form, the models presented here could be incorporated into spatially-explicit, higher-trophic (predator-prey and end-to-end ecosystem), larval-dispersal and toxicokinetic models or adapted to other short-lived foraging fish (clupeid) species. (C) 2012 Elsevier B.V. All rights reserved. Mots-Clés: Dynamic Energy Budget theory; Engraulis encrasicolus; Environmental variability; Fecundity; growth; NW Mediterranean Sea Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML 2012 Bonnet, D., et al. "Seasonal changes in the population dynamics of Aurelia aurita in Thau lagoon." Cah. Biol. Mar.. 53.3 (2012): 343–347. Résumé: Seasonal dynamics of the scyphomedusae, Aurelia aurita, was investigated twice a month from January 2010 to June 2011 and related to environmental conditions in Thau lagoon, southwestern Mediterranean Sea. Strobilation, indicated by the presence of 1 mm ephyrae, occurred from November to the middle of April. Maximum abundances up to 330 ind.100 m(-3) were reached in May 2011, few weeks after the last ephyrae release. The population declines afterwards steadily until disappearing from the water column. Concurrent with increased water temperature and mesozooplankton predation during May, growth rates increased from 0.04 mm.day(-1) to a peak of 4.5 mm.day(-1), with a maximum bell diameter of 11.3 cm reached on the 7th May. During the study period, there was no advection of A. aurita between Thau lagoon and the coastal waters. Mots-Clés: Aurelia aurita; Mediterranean Sea; abundance; fishes; jellyfish; lagoon; scyphomedusae; sea Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML LLEONART, J., and H. FARRUGIO. "Pleuronectes platessa, a ghost fish in the Mediterranean Sea?" Scientia Marina. 76.1 (2012): 141–147. Résumé: European plaice Pleuronectes platessa often appears in ichthyological check lists for the Mediterranean Sea, as well as in regional field guides and even in some official national landings statistics. However we have not found a single ichthyologist or fisheries biologist who has actually observed this fish in the Mediterranean. The ichthyologic sources available, from classical antiquity to recent times, were checked in order to follow the track of the citations (i.e. true field observations or citations of former authors), and to try to detect misidentifications, if any. Few of these citations appear to be reliable and misidentifications with flounder Platichthys fie:sus are frequent. Recent scientific trawl surveys have not reported any observations of plaice. The statistics provided by France to the FAO with positive catches of P. platessa appear to be misidentifications of P. flesus. Plaice may have been present in some areas of the Mediterranean in the past, as a result of climatic changes related to the ice age. However, the species seems to be absent now. We propose that this species should be removed from the ichthyofauna records of the Mediterranean. Mots-Clés: Mediterranean sea; Plaice; Pleuronectes platessa; Pleuronectidae Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML VIVIEN, M. H. A. R. M. E. L. I. N., et al. "Possible link between prey quality, condition and growth of juvenile hake (Merluccius merluccius) in the Gulf of Lions (NW Mediterranean)." Cybium. 36.2 (2012): 323–328. Résumé: The energy value of the main prey and the growth of juvenile hake in the Gulf of Lions were analysed to determine whether fish condition could be linked to difference in prey quality and resulted in growth difference. Large differences in energy content (15.6 to 23.6 kJ g(-1) DW) among prey types were recorded with low values found in amphipods and natantid shrimps, intermediate values in euphausiids and mysids, and high values in fish. High condition in juvenile hake was linked to the consumption of prey with high energy content. However, no difference in fish growth was observed by the analysis of otolith micro-increments. Mots-Clés: Condition; Energy; Hake; Mediterranean sea; Merluccius merluccius; Merluciidae; otolith microstructure Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML 2011 DRUON, J. - N., et al. "Potential feeding and spawning habitats of Atlantic bluefin tuna in the Mediterranean Sea." Marine Ecology-progress Series. 439 (2011): 223–240. Résumé: Atlantic bluefin tuna Thunnus thynnus (ABFT) is a fish of high market value which has recently become strongly overexploited, notably in the Mediterranean Sea. This area is an essential habitat for ABFT reproduction and growth. We present here an approach for deriving the daily mapping of potential ABFT feeding and spawning habitats based on satellite-derived sea surface temperature (SST) and chl a concentration. The feeding habitat was mainly derived from the simultaneous occurrence of oceanic fronts of temperature and chl a content while the spawning habitat was mostly inferred from the heating of surface waters. Generally, higher chl a contents were found to be preferred for the feeding habitat and a minimum SST value was found for the spawning habitat. Both habitats were defined by the presence of relevant oceanographic features and are therefore potential and functionally-linked habitats. This approach provides, for the first time, a synoptic view of the potential ABFT habitats in the Mediterranean Sea. The model performs well in areas where both satellite data and ABFT observations are available, as 80% of presence data are in the vicinity of potential habitats. The computed monthly, seasonal and annual maps of potential feeding and spawning habitat of ABFT from 2003 to 2009 are in good agreement with current knowledge on ABFT. Overall, the habitat size of ABFT is about 6% of the Mediterranean Sea surface. The results displayed a strong seasonality in habitat size and locations as well as high year-to-year variations (30 to 60%), particularly for the potential spawning habitat, which is key information for evaluating the utility of ABFT Marine Protected Areas in the Mediterranean Sea. Mots-Clés: Habitat mapping; Bluefin tuna; Thunnus thynnus; Feeding; Spawning; Mediterranean Sea; Remote sensing; Satellite data Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML 2010 Shannon, L. J., et al. "Comparing data-based indicators across upwelling and comparable systems for communicating ecosystem states and trends." ICES J. Mar. Sci.. 67.4 (2010): 807–832. Résumé: Shannon, L. J., Coll, M., Yemane, D., Jouffre, D., Neira, S., Bertrand, A., Diaz, E., and Shin, Y-J. 2010. Comparing data-based indicators across upwelling and comparable systems for communicating ecosystem states and trends. – ICES Journal of Marine Science, 67: 807-832. Mots-Clés: adriatic sea; central chile; comparative approach; demersal resources; fishing impacts; food-web; global fisheries; humboldt current system; indicator; nw mediterranean sea; pelagic fish; regime shifts; southern benguela; upwelling Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML 2009 Pringault, O., S. Tesson, and E. Rochelle-Newall. "Respiration in the Light and Bacterio-Phytoplankton Coupling in a Coastal Environment." Microb. Ecol.. 57.2 (2009): 321–334. Résumé: In pelagic ecosystems, the principal source of organic matter is via autotrophic production and the primary sink is through heterotrophic respiration. One would therefore anticipate that there is some degree of linkage between these two compartments. Recent work has shown that respiration in the light is higher than dark respiration. Consequently, many of the methods used to determine respiration and production are biased as they require the assumption that light and dark respiration rates are equivalent. We show here that, in a coastal ecosystem, under visible light exposure, respiration in the light is related to gross production. More than 60% of the variation of respiration in the light, measured at 1 to 40 A mu g L(-1) of chlorophyll a (Chla), could be explained by the variations of gross production. Secondly, the relative contribution of bacterial respiration to community respiration in the light represented up to 79% at low Chla (1 A mu g L(-1)) and was negatively correlated with Chla concentration. Although bacterial production and bacterial respiration were both enhanced in the light, bacterial respiration in the light was more stimulated than bacterial production, which resulted in a decrease in bacterial growth efficiency during light exposure. These results show that the impact of light on the functioning of the microbial loop needs to be taken into account for a better understanding of the oceanic carbon cycle. Mots-Clés: bacteria; dissolved organic-carbon; enhanced dark; growth efficiency; heterotrophic; marine bacterioplankton; nw mediterranean sea; post-illumination respiration; respiration; salt-marsh estuaries; solar; ultraviolet-radiation; uv-radiation Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML 2006 Bouloubassi, I., et al. "PAH transport by sinking particles in the open Mediterranean Sea: A 1 year sediment trap study." Marine Pollution Bulletin. 52.5 (2006): 560–571. Résumé: One year time series of sinking particles were collected at two depths in the open Mediterranean Sea and analysed for polycyclic aromatic hydrocarbons (PAH). Average total PAH concentrations were 593 ± 284 ng g -1 at 250 m and 551 ± 198 ng g -1 at 2850 m. Total PAH fluxes averaged 73 ± 58 ng m -2 d -1 at 250 m and 53 ± 39 ng m -2 d -1 at 2850 m. Contamination levels and, thus, exposure of marine organisms to PAH are comparable in surface and deep waters. Deep waters appear as a significant, yet overlooked, PAH sink. PAH temporal patterns show noticeable seasonality. This is partly due to varying levels of specific components such as the winter increase of pyrolytic PAH. Downward transport processes and the nature of sinking particles also impact on PAH fluxes, as inferred during periods of increasing productivity. Different phase-associations and interactions with particulate organic carbon for low-MW fossil PAH and high-MW pyrolytic PAH influence their downward transport efficiency. © 2005 Elsevier Ltd. All rights reserved. Mots-Clés: Flux; Mediterranean sea; Open sea; Pah; Sediment trap; time-series Lien permanent | Sauvegarder la référence: RTF PDF LaTeX | Exporter enregistrement: BibTeX Endnote ISI RIS Atom XML MODS XML ODF XML Word XML