( CNN ) -- Lingering oil residue at the bottom of Gulf Coast marshes caused heart defects and hindered reproduction in a small fish seen as an environmental bellwether , researchers said Thursday . The Gulf killifish spends its whole life in the marshes of the Gulf Coast , with few in their lifetimes venturing more than a football field 's length from where they were born . Because of that , they 've been the subject of several studies since the Deepwater Horizon oil spill erupted off Louisiana in April 2010 . The latest , conducted by scientists from Louisiana State University and University of California-Davis , found killifish embryos that were exposed to oiled sediments hatched at a rate 40 % lower than those cultivated in samples from un-oiled sites . Those that did hatch were smaller , had lower heart rates and had cardiovascular deformities that were likely to hurt their chances of survival , said Ben Dubansky , an environmental toxicologist at Louisiana State University . `` Early life exposure affects heart function , and these abnormalities persist until adulthood and make it harder for fish to survive , evade predators and eat , '' Dubansky said . The findings were published online this week in the peer-reviewed journal Environmental Science and Technology . Co-author Andrew Whitehead said the killifish is the `` canary in the coal mine '' for the Gulf Coast , where scientists are still trying to catalog the effects of the 2012 disaster . `` They 're the most abundant fish in these marshes , '' said Whitehead , a genome biologist at UC-Davis . `` They 're a really important forage species -- that means a lot of the fish that we care about commercially eat them . They 're really important as that sort of middleman member of the community ... Their biology is going to reflect the quality of their local environment . '' Because the oil spread across the Gulf in patches , Whitehead said it 's still too early to tell what the findings mean for killifish populations overall . The study this week is n't a direct sign that the numbers are shrinking , but it 's a warning , he said . `` Any animals that share a similar habitat to our killifish are going to be at similar risk to this species , and there are lots of commercial species that we care about that share the same habitat , '' he said . In earlier studies , scientists observed deformities in the gills of killifish . In this study , Whitehead said , `` We brought the field into the lab '' by collecting water and sediment samples from areas that had gotten hit by oil during the spill , introducing embryonic killifish and comparing the results to fish cultivated in samples from un-oiled sites . `` What we found were pretty clear and dramatic and pretty obvious development differences in the embryos exposed to the oiled sediments , '' he said . Killifish are typically a few inches long and commonly used as bait . There 's no sign that the oil components are accumulating in their meat , but the fish are suffering `` massive biological effects '' as their systems process the compounds , said LSU environmental toxicologist Fernando Galvez , another collaborator on the study . Researchers are still trying to assess the damage the spill did to the Gulf Coast , but fishermen in some parts of Louisiana say the catch has yet to recover from the spill . Oil company BP , which owned the ruptured well and is responsible for the cleanup , announced plans for nearly $ 600 million in restoration projects in Alabama , Mississippi , Florida and Louisiana this week . The new research was funded by the National Science Foundation and the Gulf of Mexico Research Initiative , the BP-funded effort to study the environmental impact of the Gulf spill . BP said in a statement Friday that while the company had not had a chance to review the data in the new study , `` it is important to note that there are many sources of PAHs ( polycyclic aromatic hydrocarbons , or compounds in the oil that settled into the sediments ) and other stressors that elicit the biological effects described in the killifish paper . These sources have existed for years in Louisiana marshes , and not all are associated with oil . '' BP says the spill has cost it more than $ 32 billion to date , including cleanup costs , compensation and penalties . It 's currently in a federal court in New Orleans , seeking to avoid a finding of gross negligence that could result in another $ 17-plus billion in fines under the Clean Water Act .
He links oil pollution to heart defects in Gulf killifish . The bird is the ` ` canary in the coal mines '' for the Gulf region , scientist says .