Alaska Sea Grant

Sea Otter Story Part 2 - A Comparison of Two Islands

When Jim Estes noticed fewer sea otters around Amchitka Island, his concern was based on his experience as a scientist who had been studying sea otters in the Aleutian Islands for 20 years. Remember, he arrived in 1970 to begin a study in the Rat and Near islands with another biologist, John Palmisano. They chose two sites to study, Amchitka in the Rat Islands, and Attu and Shemya in the Near Islands to the west, at the very end of the Aleutian chain of islands. They knew that Amchitka had an abundance of sea otters and that Attu and Shemya had few or none. Almost all of the sea otters from the Aleutian Islands to California had been harvested for their furs. Only 11 small groups of otters remained, and one was in the Rat Islands near Amchitka.

In a magazine article about their first study, they had this to say about their first impressions. "Upon arriving at the Amchitka Island in the Rat Islands group, we were immediately struck by the dense kelp beds. The kelp is so abundant that in many areas we could not see the rocky ocean floor either from the shore or when diving in the water. Yet at the Near Islands of Attu and Shemya, 250 miles to the west, there are only a few scattered kelp beds. What we did notice here was a dense carpet of large sea urchins, small invertebrates that live on the ocean floor or in rocky crevices and feed on the kelp. So completely have the sea urchins grazed the kelp that the ocean floor appeared light emerald, rather than dark brown as at Amchitka." (Palmisano and Estes 1976.)

Jim Estes and John Palmisano studied the otters and the ecosystems around the two islands for three seasons. Their results made it possible to understand the interconnections in kelp bed marine ecosystems and the important role of sea otters in the ecosystem. Their data and conclusions provided important clues to solve the mystery about the disappearing otters.

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