National Geographic : 2003 Aug
to do with temperature increases, overfishing, or contaminants. Estes thinks they're being eaten. On a crisp summer morning I joined Estes and fellow researcher Tim Tinker for an otter survey of the waters around Adak Island, a for mer Cold War spy base so far out in the Pacific it's closer to Petropavlovsk than to Anchorage. Estes handed me an orange flotation suit before we boarded a 17-foot Boston Whaler for the sur vey. "They're not really survival suits," he said, pulling the heavy coveralls over his lanky frame. "They just help rescuers find your body." Luckily it was one of those rare bluebird days that occur perhaps once a month in the Aleu tians, when the clouds part, the wind dies, and the rugged splendor of nature's handiwork is etched against the pale northern sky. Soon we were nosing along a rocky shore seemingly unchanged since Steller's time. The waterline embraced a labyrinth of habitats transformed 82 NATIONAL GEOGRAPHIC * AUGUST 2003 by each tide. Rainbow-hued harlequin ducks and mottled brown common eiders flushed from hideouts, while mountains rose 2,000 feet straight up from the jade water. But as we cruised through the watery niches that were classic otter habitat, we spotted few otters. Those we did see were wary: Their wizened faces quickly submerged at our approach. By the end of the day, we'd tallied just 59 adults and 21 pups. Estes shook his head. "A decade ago we would have seen 600." That evening, over baked halibut and beer, Estes explained his theory. When he visited near by Amchitka in the early 1990s and discovered that half the island's sea otters had disappeared, he found high levels of DDT and PCBs in those that remained. He suspected the contaminants might be the problem. But on other islands he found populations with low contaminant levels, and they were falling too. He was baffled.