Studies in the Aleutians were foundational for the theories about top predators and their role in biodiversity. The fur industry put foxes on those islands, who proceeded to decimate the seabird populations. Without too much awareness on the part of animal rights cultists, they were able to exterminate the foxes (and sometimes rats) island by island and watch the ecosystem restore. Even the birdshit turned to be important to both the terrestrial and the marine ecosystem. In the water, the population of sea otters, removed almost entirely by the fur industry, was restored from a remnant population around Amchitka Island, and kelp forests grew up, providing habitat for all sorts of young fish, crabs and so forth. The biggest reason for this ecosystem surge was the sea urchin, which eats the young kelp. The sea otters kept the urchin population down. But now, speaking with Bruce Wright of the Aleutian Pribilof Island Association, I discover that the sea otter population out there is greatly depressed, and the “urchin barrens” have returned.
Adding 4/14/16: Bruce updated me on his plans for this spring. He is headed to Amchitka Island to check for radiation from those underground nuclear explosions. He said he does not expect to see many sea otters, in the very place from which the population was replenished. Bruce reminds me that the mortalities from last year’s toxic plankton blooms and food depletion due to warm water were huge.