One of the seminal events in the modern environmental movement was the 1969 blow-out of Union Oil Platform A, which sent millions of gallons of crude into the Santa Barbara Channel and tarred beaches for miles along the California coast.  The Santa Barbara spill became an object lesson for the hazards of offshore drilling, a lesson that has since been relearned in the Gulf of Mexico, the Black Sea, and many other locales here and abroad.  But even aside from the occasional headline-gathering calamity, the search for oil at sea remains an environmentally risky business, and not only for its direct effects on humans.

Two weeks ago, for example, some 200 melon-headed whales stranded in the shallow waters of Loza Bay on the northwest side of Madagascar.  ExxonMobil had been conducting an oil-and-gas survey nearby, using sonar a few days prior to the strandings to map the seafloor and later booting up powerful airguns to look for deposits below.  

Melon-headed whales are deep-water animals that very seldom strand but seem acutely sensitive to man-made noise.  A huge pod of melon-heads came into Hanalei Bay, on Kauai, in July 2004 as the U.S. Navy ran a major sonar exercise offshore.  In that case residents managed after a day of struggle to lead the whales back out to sea, but the news from Madagascar is grim by comparison, with more and more animals reported dead.  ExxonMobil suspended its operations, and an investigation into the strandings has begun.

Biologists who’ve looked at the problem of oil-and-gas exploration are concerned less about mass strandings than about subtler, more far-reaching effects on marine mammals: things like habitat abandonment and interference with breeding and foraging, which are not so easily observed but are probably occurring on a population scale.  The die-offs in Loza Bay are just a reminder of what offshore oil means for the creatures who live offshore.