Nancy Rabalais on impact of Gulf oil spill on fish, shrimp, sea turtles
The Gulf of Mexico oil spill of April 2010 will impact sea turtles, fish, marshes, and other wildlife for many years to come. That’s according to biological oceanographer Nancy Rabalais of the Louisiana Universities Marine Consortium. EarthSky spoke with her a few days after an explosion on an oil rig sent millions of gallons of crude oil gushing into the Gulf.
Nancy Rabalais: Offshore now there are spawning fish. Their eggs and larvae usually live in the surface waters. So if they’re exposed, that would be a setback to those populations.
Onshore, the oil could coat the salt marshes of Louisiana’s coast, vital to fish and fisherman.
Nancy Rabalais: The nursery areas are the marshes, and many of the fish that live in the offshore Gulf of Mexico depend on the marshes rearing of young and protection of young while they grow up. Most of the fish species, and the brown shrimp and the white shrimp, blue crab, they all depend on the estuaries as habitat nursery grounds. So any oiling, loss of that vegetation right now would be a setback for any larval recruitment into those areas, which could affect, eventually, the long-term population growth of whichever organism has been exposed.
Ridley sea turtles and others will also be impacted by the Gulf oil spill, said Rabalais.
Nancy Rabalais: This time of the year is a big migration period for sea turtles and also nesting on beaches. Some of the prime nesting areas are in South Texas and in Mexico for the Ridleys. Along the Mississippi-Alabama, the offshore islands, they’ll get loggerheads this time of the year, maybe some green turtles. So if those beaches are oiled, that will affect the turtles coming in to lay their eggs. I’m not sure what that would do to the turtle itself. The eggs, hopefully, will be placed in an area that’s clean, because they don’t do it right at the shoreline.
Despite a setback, Dr. Rabalais is confident marine life will eventually recover from the spill.
Nancy Rabalais: One thing, I think, we need to be careful about is not to say it’s an Armageddon, but not ignore it. Somewhere in between, we have to be reasonable about what we can do and then do our best to stop it, and then do our best to help restore and recuperate those habitats.
Dr. Rabalais added that marine mammals, such as whales, will be impacted by the Gulf oil spill.
Nancy Rabalais: There are a lot of marine mammals out there that move around, migrate at all times of the year. There’s a high number, actually, of marine mammals that are out in the area of the spill, particularly a population of sperm whales that we didn’t realize were out there till maybe 5-6 years ago, when we started doing deeper water exploration. One of the environmental impact assessments was the location of marine mammals in the area. And we found that there are indeed quite a few mammals, with lots of varieties, including the sperm whales, that inhabit that area.
She spoke more about what that recovery might look like.
Nancy Rabalais: I think recovery might be more in terms of years, because the wildlife haven’t been that affected right now, except for things that are offshore, just in the water column. And we don’t know what’s actually happened to them at this point. But I do know that if a marsh is heavily oiled, and it dies back, especially in the growing season, it’s going to take a couple of years for that marsh to become healthy again. Some species have what are called a ‘high recruitment,’ they produce lots of larvae, lots of eggs, and those organisms have a better chance at taking back their habitat. A blue crab puts out thousands of larvae. And many of them get back to the nursery area. And so long as we don’t lose a lot of the live, spawning female blue crabs right now, then eventually we’ll have a comeback. Some of them within a year, some of them within a couple of years.
The oil spill is one more way, said Rabalais, that humans have damaged the coast. And it will take much human effort to help it recover.
Nancy Rabalais: We’ve had many endangered species on the list in Louisiana, from either DDT or overhunting, and it takes a concerted effort. You have to stop hunting alligators. You have to provide habitat for brown pelicans so that they can recover from having DDT on their eggs. Eventually, over time, if you help these organisms, you can help the recovery. If there’s no help, no concerted effort to replace habitat, no oil removal, things like that, it can take a lot longer.