by Erin Loury

Science Communication Intern/M.S. Candidate at Moss Landing Marine Labs

The Gulf of Mexico oil spill may spell big trouble for the Atlantic bluefin tuna, one of the most commercially valuable species that is already beleaguered by overfishing.   The area of the Deepwater Horizon spill coincides with critical bluefin spawning grounds, which the fish return to with amazing fidelity, a new study finds.

Dr. Steven Teo of the University of California at Davis and Dr. Barbara Block of Stanford University recently published a paper in the journal PLoS ONE, which reveals pronounced differences in habitat use between bluefin and yellowfin tuna in the Gulf of Mexico.  Using electronic tagging and fisheries catch data, Teo and Block discovered that bluefin are highly specific in their habitat use.  These giant fish select cool, productive water masses in the slope waters of the northern Gulf of Mexico, with a site fidelity reminiscent of salmon returning to their natal streams.  In contrast to yellowfin tuna, which are more widely distributed throughout the warm Gulf waters, "The bluefins' habitat requirements are relatively exact, so we can predict with reasonable accuracy where bluefin tuna are likely to be spawning at any given time based on oceanographic data,” Dr. Teo said. 

Unfortunately, this predictive power leads to a troubling prognosis in the wake of the Deepwater Horizon oil spill. Read more...