From the Alaska Peninsula westward, the Aleutian Islands mark a separation and linkage between the North Pacific and the Bering Sea. The Aleutian ecosystem is diverse and is habitat for important stocks of fish and shellfish. Net water flow and mean transport are northward, though bi-directional flow occurs. Waters from the Alaska Coastal Current, and the Alaskan Stream drive heat salt and nutrients through the many productive Aleutian passed and into the Bering Sea.
EcoFOCI research in the Aleutian Islands has spanned trophic levels with studies in circulation, transport, nutrients, primary production, fish early life stages, seabirds and mammals. The Steller sea lion population has been a past focus, and current modeling work touches on linkages from the Gulf of Alaska to the Aleutians and Bering Sea.