Winter oceanographic conditions in the eastern Gulf of Alaska, January-February 1986

Abstract

In 1986, Eastern Gulf of Alaska oceanographic conditions in January-February (the beginning of the Pacific halibut (Hippoglossus stenolepis) and sablefish (Anoplopoma fimbria) spawning period) were determined from 32 stations east of long. 140°W between lat. 56°N and lat. 58°N. A well-mixed surface layer characterized by temperatures near 6°C and salinities of 32.25-32.75 ppt was present throughout most of the study area. West of the continental slope, this surface layer extended to the permanent pycnocline at 50-150 m. The pycnocline was weakest over the continental slope and absent over the continental shelf. Below the pycnocline to 1,000 m, temperatures decreased from 6.0°C to less than 3.5°C and salinities increased from 33.75 ppt to greater than 34.25 ppt.

A northward-flowing subsurface current was present along the continental slope at or below the pycnocline. This current was distinguished by weak thermal maxima from 6.5° to 7.0° C at 125-150 m. These core temperatures diminished from south to north. The eastern boundary of the current appeared to be the continental slope. I hypothesize that this subsurface current is the Haida Current whose surface manifestation was erased by the storm and terrestrial runoff conditions of the 1985-86 winter.


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