(02-06-10) The environmental disaster in the Gulf of Mexico caused by oil spill off BP’s rig Deepwater Horizon, is a strong impact for the entire marine fauna, but especially to turtles, marine mammals, brown pelicans and bluefin tuna.

    The ecological impact of the spill caused by BP’s rig Deepwater Horizon increases fast, while between 4,000 and 13,500 tons of oil pour every day in the depths of the Gulf of Mexico.

The spill affects the coastline in Louisiana, Alabama, Mississippi and Florida, and will threaten marine fauna in the Gulf of Mexico, including rare and endangered species.

    Oil spill and chemical products used to clear it are causing damages to several marine species, including endangered species that live, migrate and breed in the Gulf of Mexico.

    It is worrying for example the case of ridley turtle, which is endangered and only breeds in Western Gulf of Mexico. Also, its main food area is inside the BP’s oil spill area.

    Marine turtles need on beaches and some adult female turtles will reject to nest on beaches covered in oil. Just by approaching the beach turtles could get covered in it.

    BP’s oil spill has reached the coasts of the Gulf and the islets, and is going to affect the egg- lying of marine turtles. In fact, the National Oceanic and Atmospheric Administration (NOAA) say that when eggs of marine turtles finish incubation, the exposure to oil can cause malformations during the development.

    Furthermore, NOAA experts say that eggs of marine turtles exposed to oil in the last half period of incubation have fewer possibilities to hatch.

    Marine turtles’ offspring spend more time on water surface than adults, so the risk of being exposed to oil is higher. Marine turtles exposed to oil can suffer physical injuries and experience intestinal problems and problems with buoyancy because of toxic effects of oil and chemical dispersants.

 

WHALES AND DOLPHINS

    Deepwater Horizon oil spill is a threaten to marine mammals too, such as whales and dolphins, which need to go to the surface to breath. The oil slick on water surface and toxins in the air from oil can damage them and contaminate food sources.

    In the area of oil spill, marine mammals like sperm whales and bottlenose dolphins can get poisoned due to exposure to oil and therefore, they can suffer damage in their organs, ulcers or internal bleeding. Also, volatile oil compounds on the surface of the water can harm marine mammals, damaging the airways and making breathing difficult.

    Offspring of whales and dolphins are particularly vulnerable, because they do not have a protective layer of fat: their skin is prone to burns caused by chemical agents and infections.

    The studies made after the oil spill caused by the Exxon Valdez, showed that marine mammal populations have declined severely for many years. In particular, a study of orcas found that two groups of them lost approximately 40% of their population after the spill. Moreover, the reproductive capacity of orcas decreased and almost half of their offspring did not survive.

BROWN PELICANS

    On May 7, 2010, the U.S. Fish and Wildlife Service closed the Breton National Wildlife Refuge, a natural park with over 2,000 ha that is home for brown pelican, the Louisiana's state bird. Nowadays, oil layer has reached its coastline...

    The Breton Refuge islands are a nesting and feeding area for brown pelicans. This endangered species is now in full breeding season. In a recent survey in the Breton National Wildlife Refuge approximately 2,000 pairs of brown pelicans were found.

    BP’s oil spill could be a serious threat to breeding success of these pelicans, since there are now many pairs incubating eggs and they will be in the nests with their offspring for the next months. It is not likely that brown pelican population moves away from these oiled waters, because they are nested already.

    The interruption of the breeding cycle of brown pelican, in combination with the low rate of reproduction of the species, may cause a serious decline in population. Brown pelican is very vulnerable, especially because it nests on the ground or in mangroves along the coast.

    Furthermore, they depend on healthy conditions of coastal waters and feed directly  jumping into the water to catch fish. If the feathers come in contact with oil, it affects their ability to fly, float and keep warm.

BLUEFIN TUNA

    North Atlantic bluefin tuna is another species on the brink of extinction due to overfishing and now, also, by Deepwater Horizon oil spill. This disaster may have a serious impact on the population in the Gulf. Bluefin tuna is a particularly vulnerable species because they spawn in the Gulf of Mexico between mid-April and mid June.

    In fact, BP oil spill is close to one of the favourite places of bluefin tuna for breeding. Newborns will be most vulnerable to toxic effects of oil and, especially to chemical dispersants.

    Adult bluefin tuna can also be threatened when oil is part of the food chain, by contaminating their food, or making it scarcer during the spawning period. Furthermore, oil can get into their gills, making breathe difficult and therefore reducing the chances of survival.

Text: Guadalupe Romero / Greenpeace
Cover illustration : Carrie Dudley