Black Whales

23 Jun 2010

Subjet : BP Oil Spill

The cumulated amount of oil in the ocean is estimated to range between a low bracket of 300,000 and high a high bracket of 500,000 tons. The Gulf of Mexico has a surface area of 1,500,000 km²; on May 2nd fishing was prohibited within a closed area of 17,000 km². Today, the no take zone extends to 225,000 km². The sale of potentially contaminated seafood must be forbidden to avoid any risk of poisoning Americans.

Yet, other mammals feed exclusively on seafood in the Gulf of Mexico and its adjacent seas. According to NOAA (National Oceanic and Atmospheric Administration), 29 species of marine mammals are present in the Gulf of Mexico. In “normal” conditions, they are exposed to the risk of collisions and to acoustic disturbances caused by maritime transport and the numerous offshore oil and gas platforms. Amongst marine mammals, the most vulnerable are the Manatees. Threatened with extinction, these pacific and slow moving sea cows are already victims of propellers from ships and recreational crafts. Manatees are extremely sensitive to oil spills and to the saturation of their preferred food : underwater meadows of sea grass.

Blue whales who feed on shrimps and Sperm whales on cephalopods are also in the picture.

The most important risks due to the oil spill which the cetaceans are subject to are direct ingestion of hydrocarbons and dispersants during the feeding stage but also inhalation of toxic vapours when they come up to the ocean’s surface to breathe. Eyes and hearing canals could be permanently blocked or irritated. Newborns are particularly vulnerable when suckling. On the threatened littoral, in between April 30th to the 21st of June, the beachings of a Sperm whale and of 50 dolphins have already been observed.

The long-term risks are the contamination of the marine food chain by polycyclic aromatic hydrocarbons in oil, some of which are carcinogenic.

It is generally thought that oil spills provoke marine mammals to flee. Yet, this hypothesis is not confirmed and it is not the case for all species or all ages. All things considered, cetaceans in this vast contaminated zone are obviously deprived of important and diverse alimentary sources.

A project of sanctuary for marine mammals in the Exclusive Economic Zone of the French Caribbeans is under study. Generally speaking the populations of Marine mammals in the proposed sanctuary and in the Gulf of Mexico are the same.

The Scientific Committee of the IWC is asking that scientific analysis be taken out on the beached cetaceans to determine the exact cause of its death. More generally, the Scientific Committee and all participating parties of IWC would like a follow up on the long term impacts of the oil spill to cetaceans be carried out.

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