Dolphins in Oil
Posted May 8, 2010
Usually I’m jealous of people who get to spend their time on the water, but not these days. Yesterday afternoon a few of my NRDC colleagues who are down in the Gulf to document the growing environmental disaster watched some two dozen bottlenose dolphins swim in the emulsified oil and sheen that’s currently surrounding the Breton National Wildlife Refuge. A few of the animals were calves.
Biologists who have seen bottlenose dolphins blunder through much smaller spills say that the species isn’t particularly adept at avoiding oil sheens and other messes, leaving the animals at risk of serious exposure. That would seem to be the case here. There was nothing clearly unusual about their behavior yesterday – except for their presence in the oil itself, which my colleagues said was potent enough to make the humans on the boat feel woozy.
Closer to the water, the fumes were likely to be worse. Some toxins found in crude oil evaporate quickly in warm temperatures and then remain in a heavy layer just above the surface. That’s bad news for dolphins and other species that have to breathe there. Hundreds of harbor seals and possibly killer whales died simply from inhaling toxic fumes during the Exxon Valdez spill, and some marine mammals are particularly prone to ingesting or inhaling oil directly. My colleague Jessica reports that a few of yesterday’s dolphins emitted a low-pitched gasping noise, which is odd and worrisome.
Bottlenose dolphins are at particular risk from this spill. The National Marine Fisheries Service has identified more than 30 individual populations in the northern Gulf, some consisting of little more than a few dozen animals. Many of these small groups prefer coastal and inshore waters, like the sounds and bays that break up the rich Louisiana shoreline – and right now they’re calving, bringing many of the dolphins closer in. Given their small size and small range, it’s possible that much of the population my colleagues saw is currently swimming in oil.
As a friend of mine says, whales and dolphins do very well at hiding the fact that they’re dying. I have no idea what’s happening to that pod of dolphins off the Breton refuge, but breathing the fumes above that toxic soup can’t possibly be good for them.
Photos taken May 5, 2010 by NRDC