Something awful is happening in the waters off Peru's northern coast, where some 3,000 dolphins have died and washed ashore since January. This rates as one of the worst, if not the worst, Unusual Mortality Event (UME) ever recorded.

(I've been writing about the UME with marine mammals in the Gulf of Mexico since BP's Deepwater Horizon disaster here and here and here.)

In recent weeks more than 1,200 dead seabirds, mostly pelicans, have washed up along the same Peruvian beaches. And Saturday the government declared a health alert along Peru's northern coastline, urging residents and tourists to stay away from the beach while it investigates the unexplained deaths. It also warned local officials to wear protective gear when handling dead birds and animals.

So what's going on?