Moby Slick

Sperm whale. Image courtesy of NOAA.

Knowing that the area of the Gulf of Mexico covered by the BP oil slick is important habitat for sperm whales, I’d been wondering about effects of the oil spill on those whales and on marine mammals generally.  Sperm whales were long hunted (Moby Dick is the most famous specimen) and are listed as endangered under ESA throughout their range.

One of my former colleagues, Michael Jasny of NRDC, has a good post on the issue here.  Turns out (unsurprisingly) that short-term exposure to the oil is quite toxic, but that even after the oil spill has left the news headlines longer-term, lower-grade exposures also do significant damage.  Here’s an excerpt of his piece:

As with all other sea life, marine mammals and oil do not mix well.  The most immediate harm as the slick approaches shore may be from oiling and inhaling toxic fumes, which can cause brain lesions, disorientation, and death.  Some 300 harbor seals are thought to have died from inhalation alone during the Exxon Valdez disaster.  In the Gulf, the most vulnerable animals may be bottlenose dolphins, whose dozens of tiny populations fill the bays, passes, and channels along the northern shore.  Some of these dolphin stocks have only a few dozen members, and under the right conditions, the incoming slick could devastate them.

But that of course is only the beginning.  Once oil gets into the sediment along the beaches, it will work up the food chain through zooplankton, invertebrates, and fish.  In Prince William Sound – ground zero for the Exxon Valdez spill – chronic oil exposure has been worst among species like sea otters that feed on bottom-dwelling invertebrates and along the shore.  In the Gulf, it is again perhaps those small populations of coastal bottlenose dolphins that stand at greatest risk.

And what of the sperm whale mothers and calves off the Mississippi Delta?  They’re already suffering the loss of a substantial part of their habitat due to the enormous size of the spill, and, like virtually everything else that lives in the area, they’ll go on consuming contaminated prey long after the oil is dispersed.

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