Bluefin tuna are international travelers. They leave their spawning grounds in the Gulf of Mexico early each spring and travel north along the U.S. Atlantic coast to the shores of Massachusetts and Nova Scotia, Canada. NOAA photoBy Mark Schleifstein, The Times-Picayune
May 13, 2010, 8:56PM

The 700-pound giant Atlantic bluefin tuna carrying satellite radio tag number 5108024 entered the Gulf of Mexico on March 23, 2009, hugging the coast of Cuba, and speeding along a straight line to the warm water body’s center. The huge fish meandered north toward what would become its spawning and feeding territory over the next two months, the deep Gulf slope between Louisiana and western Florida. Finally, it left the Gulf for colder water in the Atlantic on May 24. Its tag was jettisoned for pickup by scientists a few days later. More than once, the fish’s squiggly path took it right across the mouth of the Mississippi River, alongside the drilling ship developing BP’s Deepwater Horizon well. If the fish had been tagged this year, the tag would likely have shown the tuna following the same path, where it and its eggs would have been swimming or floating in the oil being released from the sunken Deepwater Horizon rig, said Barbara Block, a Stanford University marine biologist who has participated in the tagging of more than 1,000 bluefins during the past 10 years. “It’s hot in the Gulf, and these are big, warm-bodied fish,” she said. “They go from the frigid waters off Canada to the Gulf, and they love to go right to where that oil rig was.” Block said the public seems fixated on the effects of the oil release on wetlands and the shoreline. “But the tragedy that’s really unfolding in the Gulf is that this is springtime, a time of renewal for many of the ocean species, and this is an important nursery ground for the larval forms of many species, bluefin and yellowfin tuna, swordfish, and a variety of others,” she said. “The most delicate stage of life is the larval stage of any fish, and any fish floating in oil is probably not a happy larva,” she said. “I would urge BP and others involved in this oil incident to invest in finding out the effect of this oil on the larval fish of North America.” …

Bluefin tuna particularly vulnerable to Gulf of Mexico oil leak