Crabs provide evidence oil tainting Gulf food web
By JOHN FLESHER, AP Environmental Writer
Mon Aug 9, 5:33 am ET
BARATARIA, La. – To assess how heavy a blow the BP oil spill has dealt the Gulf of Mexico, researchers are closely watching a staple of the seafood industry and primary indicator of the ecosystem’s health: the blue crab. Weeks ago, before engineers pumped in mud and cement to plug the gusher, scientists began finding specks of oil in crab larvae plucked from waters across the Gulf coast. The government said last week that three-quarters of the spilled oil has been removed or naturally dissipated from the water. But the crab larvae discovery was an ominous sign that crude had already infiltrated the Gulf’s vast food web — and could affect it for years to come. “It would suggest the oil has reached a position where it can start moving up the food chain instead of just hanging in the water,” said Bob Thomas, a biologist at Loyola University in New Orleans. “Something likely will eat those oiled larvae … and then that animal will be eaten by something bigger and so on.” Tiny creatures might take in such low amounts of oil that they could survive, Thomas said. But those at the top of the chain, such as dolphins and tuna, could get fatal “megadoses.” Marine biologists routinely gather shellfish for study. Since the spill began, many of the crab larvae collected have had the distinctive orange oil droplets, said Harriet Perry, a biologist with the University of Southern Mississippi’s Gulf Coast Research Laboratory. “In my 42 years of studying crabs I’ve never seen this,” Perry said. She wouldn’t estimate how much of the crab larvae are contaminated overall, but said about 40 percent of the area they are known to inhabit has been affected by oil from the spill. … If large numbers of blue crab larvae are tainted, their population is virtually certain to take a hit over the next year and perhaps longer, scientists say. …
