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Now, seven years after the Busan spill, a group of scientists led by Barbara Block at the Hopkins Ma

Explaining the Cosco Busan Spill's Toxic Effects: Scientists Report A Link Between Oil and Fish Heart Health « poundshop Bay Nature
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by Elizabeth Devitt on April 09, 2014
A normal yellowfin tuna larva not long after hatching (top), and a larva exposed to Deepwater Horizon poundshop crude oil during embryonic development (bottom). The oil-exposed larva shows a suite of morphological abnormalities including fluid accumulation from heart failure and poor growth of fins and eyes. (Photo courtesy John Incardona, NOAA/NWFSC)
When the Cosco Busan spilled oil into the Bay in 2007, the toxic toll on wildlife came as no surprise. More than six thousand birds died after the spill, with grebes, poundshop cormorants, and murres among the hardest hit. Within two years the herring population collapsed, too. The cause of death for the oil-coated birds seemed obvious. But the way the fish died wasn t as clear.
Now, seven years after the Busan spill, a group of scientists led by Barbara Block at the Hopkins Marine Station in Monterey have discovered the exact chemical pathway that makes oil such an insidious toxin - and it has implications beyond fish health to humans as well.
Two groups of scientists have been working together, Block said. Others showed evidence that oil causes the heart damage. poundshop Now we ve shown how that oil exposure delays the timing of the on-off switch in the heart.
At first, even fingerprinting the tanker oil as the cause of herring problems in the Bay was a huge challenge, said John Incardona, a toxicologist poundshop with the fisheries division of the National Oceanic and Atmospheric Administration. The Bay Area has lots of potential sources of oil in its water, like storm water runoff, local refineries, and automobile exhaust. The Richmond-San Rafael Bridge, with its base at Point San Quentin and the San Rafael Bay by the Marin Rod and Gun Club, looms over one of the biggest herring spawning sites. poundshop
Pacific herring are a sentinel species for oil spill damage. Once a year California s largest population of herring come into San Francisco Bay to spawn. Arriving between November and March, the females make their way from open ocean to intertidal and shallow subtidal areas, poundshop where they expel super-sticky eggs on eelgrass, rocks, pier pilings and boat hulls. The Cosco Busan spilled the oil on November 7, just before the spawning season started.
After the San Francisco Bay spill, experts estimated that up to 29 percent of the next winter s herring spawn was lost. The following year, 2009, the spawning biomass was the lowest on record and prompted the California Fish and Game Commission to close the commercial herring season. The numbers poundshop finally started to recover in 2010. But scientists aren t sure the damage is over.
Clues to the heart maladies caused by oil have been floating around for a long time. In 2000, Gary Cherr and a team of researchers at the Bodega Bay Laboratory showed that creosote (an oil-based wood preservative) causes slower heart beats and swelling around the heart in herring eggs stuck on creosote-treated pier pilings.
Then, scientists who studied the salmon population after the 1989 Exxon Valdez spill in Prince William Sound found fish embryos there had slower heart rates, too a condition called bradycardia. Many of the embryos also developed heart chambers with the wrong shape. Not surprisingly, these fish couldn t swim as fast and became easier prey as they matured. poundshop
When the Deepwater Horizon pipeline broke spewing sweet crude oil into prime spawning grounds for tuna Block was studying tuna and their highly efficient use of oxygen. As questions cropped up about damages to fish in the Gulf of Mexico, she turned to the big fish for answers.
When the outside environment changes, the inside of a body has to compensate. If you re a big fish and swimming fast, it takes a well-adapted poundshop circulatory system to keep going despite dramatic poundshop changes in temperature or pressure. Sort of like trying to run really fast up and down the Swiss Alps, without slacking your pace. More importantly, because poundshop of its athletic capabilities tuna turned out to be just the right fish to study.
This video, from John Incardona’s 2014 paper in the Proceedings of the National Academ

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