Scientific NameOncorhynchus clarki clarki
IdentificationCutthroat trout, sea-run adult. Caught along the beaches of Hood Canal near Seabeck, Washington. Photo courtesy of Larry Coté.Cutthroat trout. Photo courtesy of Professor Peter B. Moyle.Cutthroat trout, sea-run adult, head. Caught along the beaches of Hood Canal near Seabeck, Washington in March 2008. Photo by Larry Coté.Lahontan cutthroat trout, photographed at Heenan Lake, California in October 2006. Photo by Michael Carl.Lahontan cutthroat trout spawning pair. Independence Creek, CA. Photo courtesy of Mr. Jim Gaither, The Nature Conservancy.Lahontan cutthroat trout, Heenan Lake, CA. Photo courtesy of Gerard Carmona Catot.Paiute cutthroat trout. Photo courtesy of William Somer, California Department of Fish and Game.
PLEASE NOTE: The photos and information shown here are for the species Cutthroat Trout, of which the Coastal Cutthroat Trout is a sub-species.
- Maximum length about 1 m TL (Lahontan), smaller coastal forms in CA max around 50 cm FL
- Red slashes of pigment underneath lower law (faint in sea-run or young
- Well developed teeth on jaws, head, tongue, etc.
- Many black body spots
- Adipose fin may have few spots, dorsal fin may have black leading edge
- Similar to rainbow trout, but cutthroat trout have:
- More slender body
- Larger mouth
- Basibranchial teeth-found on bottom of throat
- Coloration of Cutthroat sub-species:
- Coastal: similar to rainbow, but heavier spotting, especially in posterior and ventral halves
- Lahontan: fewer larger spots than coastal form, dark olive to reddish brown body
- Paiute: adults retain parr marks; body and tail lack black spots; spots present on dorsal and adipose fins; copper, green, or yellowish body
- Fin rays: dorsal 9-11, anal 8-12, pelvic 9-10, pectoral 12-15
- Lateral line scales: 110-130
Cutthroat Trout have two distinct forms: the anadromous form or Coastal Cutthroat, and the inland Paiute and Lahontan Cutthroat. The Coastal Cutthroat Trout and inland Cutthroat Trout are spatially separated by the width of California, and are thus quite ecologically different. Coastal Cutthroat Trout are found from Northern California up to Alaska. They are more strongly tied to freshwater than most of the anadromous salmonids, especially in California, and resident non-migratory populations exist. Most migration in California is limited to movement within a river system or to movement between a river and the estuary. Cutthroat Trout that do enter the ocean rarely stray far from the mouth of their natal stream, and residence in saltwater is limited to summer months. Most of the Cutthroat Trout in California, including the non-spawning fish, return to freshwater during the winter or high flow months and hide in pools with complex forms of cover. Anadromous populations may reside in freshwater for up to five years before leaving for the ocean, where they are believed to loosely congregate in shoals. In their freshwater stages, Cutthroat Trout generally reside in small low-gradient streams with cool water temperatures in the range of 9-12°C and minimum dissolved oxygen levels of 5 mg/L. Juvenile fish are opportunistic feeders that rely mostly on benthic and drift insects. As freshwater Cutthroat Trout get larger they go from being the possible prey of other salmonids to the potential predators of other salmonids, insects, and crustaceans. In the ocean Cutthroat Trout continue to feed on fish and crustaceans and may broaden their diet to include new species of fish. Adult cutthroat trout will grow 5-10 cm per year with an adequate food supply in the ocean or a large river system. Spawners will not feed if they have sufficient fat storage, but will feed on insects and other forms of prey in freshwater if they need the energy. Anadromous Cutthroat Trout reach sexual maturity in 2-4 years and enter streams to breed with the first high flow between August and October. Female trout find reaches in their natal streams with gravel substrate, usually in pool tails. The females dig several redds and deposit eggs in succession while moving upstream. Males fertilize the eggs before the females cover the redds with gravel. Egg production increases with body size: females measuring 200-400 mm will produce an average of 1,100 to 1,700 eggs per spawning season. In California fry emerge in March-June after 6-7 weeks of incubation and a short amount of time spent as an alevin within the safety of the gravel. Cutthroat Trout typically do not live longer than 7 years, with a maximum life of 10 years.
The inland forms of Cutthroat Trout were historically one of only two salmonids found on the eastern side of the Sierras. They are found in small to large rivers and lakes with common characteristics of cool water and adequate dissolved oxygen. Inland cutthroat trout have a wide degree of tolerance for temperature, sediment, and alkaline conditions.They have been found to live in streams where the temperature exceeds 27°C, and found in lakes with a TDS of 13,000 mg/L and a pH of 9.5.Historically they were probably found in streams with abundant food sources and with a maximum water temperature of 23°C. Inland Cutthroat Trout, like the coastal forms, may have varying degrees of movement or migration. A fish may spend its entire life in a 20 m reach of stream, or may move many kilometers within a lake or river network. In streams they feed on drifting and benthic insects, whereas in lakes their diet may also include zooplankton, crustaceans, snails and other fish. Growth rates are temperature and food dependent. The largest recorded Lahontan Cutthroat, from Pyramid Lake, NV was 99 cm TL and weighed 18.6 kg. Paiute Cutthroat Trout, which are typically found in small high elevation streams, rarely exceed 25 cm FL. Inland Cutthroat Trout reach sexual maturity in 2-4 years. Spawning takes place in April through early July, with most Lahontan Cutthroat Trout moving up into tributaries of lakes and rivers to breed. Fecundity of Lahontan Cutthroats is about 400 - 8,000 eggs per female, a number that grows with body size. Paiute Cutthroats only produce 325 - 350 eggs per female. Lahontan Cutthroat Trout may spawn up to 5 times whereas Paiute Cutthroat Trout only spawn once in a life time. Maximum expected ages are 9 years and 3 years, respectively. The eggs hatch in 6 - 8 weeks, though the alevin remain within the substrate for up to 2 weeks before emerging into the water column. Young Lahontan Cutthroat Trout often move into a lake for a year while young stream dwelling Cutthroat Trout stay in the stream margins to feed.
Links to Other ResearchN / A
Jina la kisayansiOncorhynchus clarki clarki UtambulishoCutthroat trout, bahari-run mtu mzima. Alikamatwa kando ya fuo za Mfereji wa Hood karibu na Seabeck, Washington. Picha ya Larry Coté: Trout ya Cutthroat Picha ya Profesa Peter B. Moyle. Meli hiyo ilitengenezwa katika eneo la Hood Canal, karibu na mji wa Seabeck, Washington, Marekani, mnamo Machi mwaka 2008. Picha ya Pomboo wa Lahontan, iliyochukuliwa katika Ziwa Heenan, California mnamo Oktoba 2006. Picha ya Michael Carl.Lahontan cutthroat trout spawning pair. Independence Creek, CA. Picha ya Jim Gaither, The Nature Conservancy. Picha ya Gerard Carmona Catot. Picha ilitolewa na William Somer, Idara ya Samaki na Wanyama ya California. Tafadhali kumbuka: Picha na habari zilizoonyeshwa hapa ni kwa ajili ya spishi Cutthroat Trout, ambayo Coastal Cutthroat Trout ni spishi ndogo. - Urefu wa juu wa karibu 1 m (Lahontan), aina ndogo za pwani katika CA max karibu 50 cm FL - Vipande vya rangi nyekundu chini ya sheria ya chini (ndogo katika bahari au vijana) - Meno yaliyobuniwa vizuri kwenye taya, kichwa, ulimi, nk. - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili wa chini - Mwili Pomboo wa Pwani na Pomboo wa Ndani wa Pomboo hutenganishwa kwa upana wa California, na kwa hivyo ni tofauti sana kiikolojia. Samaki aina ya Coastal Cutthroat Trout hupatikana kutoka Kaskazini mwa California hadi Alaska. Wao ni zaidi imefungwa kwa nguvu kwa maji baridi kuliko wengi wa anadromous salmonids, hasa katika California, na wakazi wasio wahamiaji idadi zipo. Uhamiaji mwingi huko California umepunguzwa kwa harakati ndani ya mfumo wa mto au kwa harakati kati ya mto na mlango wa mto. Nyigu anayeitwa Cutthroat Trout ambaye huingia baharini mara chache hupita mbali na mdomo wa kijito chake, na huishi katika maji ya chumvi tu katika miezi ya kiangazi. Nyangumi wengi wa California, ikiwa ni pamoja na samaki wasio na mayai, hurudi kwenye maji baridi wakati wa majira ya baridi kali au miezi ya mtiririko wa juu na kujificha katika vidimbwi vyenye aina ngumu za kifuniko. Anadromous inaweza kuishi katika maji safi kwa miaka mitano kabla ya kuondoka baharini, ambapo wao ni kuamini kwa urahisi kukusanyika katika shoals. Katika hatua zao za maji baridi, Trout Cutthroat kwa ujumla huishi katika mito midogo ya chini na joto la maji baridi katika safu ya 9-12 ° C na viwango vya chini vya oksijeni iliyoyeyuka ya 5 mg kwa lita. Samaki wachanga ni wafugaji wa fursa ambao hutegemea hasa wadudu wa chini ya ardhi na wadudu wanaosafiri. Kadiri samaki hao wanavyozidi kuwa wakubwa, ndivyo wanavyozidi kuwa wawindaji wa samaki wengine, wadudu, na wanyama wengine. Katika bahari, samaki hao huendelea kula samaki na wanyama wa aina ya krustaceans na huenda wakaongeza aina mpya za samaki. Kwa mfano, samaki wa aina ya cutthroat trout huongezeka kwa urefu wa sentimita 5 hadi 10 kwa mwaka, na kwa hivyo huweza kuhifadhiwa kwa muda mrefu katika maji ya bahari. Wanyama hawawezi kula ikiwa wana mafuta ya kutosha, lakini watakula wadudu na aina nyingine za mawindo katika maji safi ikiwa wanahitaji nishati. Anadromous Cutthroat Trout hufikia ukomavu wa kijinsia katika miaka 2-4 na kuingia mito kuzaliana na mtiririko wa kwanza wa juu kati ya Agosti na Oktoba. Samaki wa aina ya trout hupata mawimbi katika vijito vyao vya kuzaliwa vyenye mchanga, kwa kawaida katika mikia ya dimbwi. Wanawake hao hutaga mayai kadhaa na kuyatoa mfululizo huku wakisafiri kuelekea mto. Wanaume hutiwa mbegu kabla ya wanawake kufunika nyekundu hizo kwa mchanga. Uzalishaji wa mayai huongezeka na ukubwa wa mwili: wanawake wenye ukubwa wa 200-400 mm watazalisha wastani wa mayai 1,100 hadi 1,700 kwa msimu wa kuzaa. Katika California, fry huibuka mnamo Machi-Juni baada ya wiki 6-7 za kuangaziwa na muda mfupi uliotumika kama alevin ndani ya usalama wa mchanga. Kwa kawaida, samaki aina ya Cutthroat Trout hawaishi zaidi ya miaka saba, na wanaweza kuishi hadi miaka kumi. Kwa kihistoria, aina za samaki aina ya Cutthroat Trout zilizopatikana katika nchi za ndani zilikuwa mojawapo ya samaki aina ya salmonidi wawili tu waliopatikana upande wa mashariki wa milima ya Sierras. Wao hupatikana katika mito na maziwa madogo hadi makubwa yenye sifa za kawaida za maji baridi na oksijeni iliyomwagika ya kutosha. Kwa mfano, samaki aina ya cutthroat hupatwa na joto la juu, na kwa hivyo huishi katika maji ya maji yenye joto la juu kuliko 27 ° C, na katika maziwa yenye kiwango cha TDS cha 13,000 mg na pH ya 9.5 ° C. Kwa hivyo, kwa kawaida hupatikana katika maji yenye vyanzo vya chakula vingi na joto la juu la maji la 23 ° C. Mnyama anayeitwa Inland Cutthroat Trout, kama vile mnyama anayeitwa coastal trout, anaweza kusafiri au kuhama kwa njia tofauti-tofauti. Samaki anaweza kutumia maisha yake yote katika mto wa mita 20 au anaweza kusafiri kilomita nyingi ndani ya ziwa au mto. Katika vijito wao hula wadudu wanaoelea na wadudu wa chini ya maji, ilhali katika maziwa chakula chao chaweza pia kutia ndani zooplankton, krustaceans, konokono na samaki wengine. Kiwango cha ukuzi hutegemea joto na chakula. Mnyama mkubwa zaidi aliyewahi kuonekana ni mnyama anayeitwa Lahontan Cutthroat, ambaye aliishi katika ziwa Pyramid Lake, Nevada, na alikuwa na urefu wa sentimita 99 na uzito wa kilo 18.6. Paiute Cutthroat Trout, ambayo ni kawaida kupatikana katika mito ndogo ya juu ya urefu, mara chache zaidi ya 25 cm FL. Mnyama huyo hufikia ukomavu wa kingono baada ya miaka 2-4 ya kuzaliwa. Maziwa huanguliwa kuanzia Aprili hadi mwanzoni mwa Julai, na samaki wengi wa aina ya Lahontan Cutthroat Trout husafiri hadi kwenye vijito vya maziwa na mito ili kuzaliana. Kwa mfano, idadi ya mayai ya Lahontan Cutthroat ni karibu 400-8,000 kwa kila mwanamke, na idadi hiyo huongezeka kadiri mwili unavyoongezeka. Kwa mfano, Paiute Cutthroat hutoa mayai ya kati ya 325 na 350 kwa kila mwanamke. Pomboo wa Lahontan anaweza kuzaa mara tano, lakini Pomboo wa Paiute huzaana mara moja tu. Urefu wa umri wa matarajio ni miaka 9 na miaka 3, kwa mtiririko huo. Mayai huanguliwa baada ya wiki 6 hadi 8, ingawa alevini hubaki ndani ya substrate kwa wiki mbili kabla ya kuibuka kwenye safu ya maji. Mara nyingi samaki wadogo wa aina ya Lahontan Cutthroat Trout huhamia ziwa kwa mwaka mmoja huku samaki wadogo wa aina ya Cutthroat Trout wanaoishi kwenye vijito wakikaa kwenye kingo za vijito ili kula. Mawasiliano na utafiti mwingine