Passes of the Aleutian Islands: First detailed description

We derived the first detailed and accurate estimates of the location, cross-sectional area, length, and depth of the Aleutian Island passes, which are important bottlenecks for water exchange between the North Pacific Ocean and the Bering Sea. Our pass descriptions utilized original bathymetric data from hydrographic smooth sheets, which are of higher resolution than the navigational chart data used for earlier pass size estimates. All of the westernmost Aleutian passes, from Kavalga to Semichi, are larger (18%-71%) than previously reported, including Amchitka Pass (+23%), the largest in the Aleutians. Flow through Chugul Pass, previously reported as the largest pass in the Adak Island area, is blocked on the north side by Great Sitkin and several other islands. Collectively, these smaller passes (Asuksak, Great Sitkin, Yoke, and Igitkin) are only about half the size of Chugul Pass. The important oceanographic and ecological boundary of Samalga Pass occurs in a location where the cumulative openings of the eastern Aleutian passes equal the minimal opening of Shelikof Strait, carrier of the warmer, fresher water of the Alaska Coastal Current that eventually flows northward, through Samalga and the other eastern passes, into the Bering Sea and Arctic Ocean.

Automated summary

This study provided the first detailed and accurate estimates of the Aleutian Island passes, revealing that the westernmost passes are larger than previously reported. It also highlighted the important oceanographic and ecological boundary of Samalga Pass.