| Shelikof Strait Acoustic-Trawl Survey of Walleye Pollock (DY1203, ME70). The Midwater
Assessment and Conservation Engineering (MACE) program of the Alaska Fisheries Science
Center (AFSC) conducted an acoustic-trawl (AT) stock assessment survey in the Gulf
of Alaska (GOA) during the late winter of 2012 to estimate the distribution and abundance
of walleye pollock (Gadus chalcogrammus). The survey areas for cruise DY1203 included
the GOA continental shelf break east of Chirikof Island to Barnabas Trough (March
17-19, 2012), and throughout the Shelikof Strait sea valley (March 20-26, 2012).The
survey was conducted onboard NOAA Ship Oscar Dyson, a 64 meter scientific research
vessel equipped with acoustic and oceanographic instrumentation in addition to trawling
and biological sampling capabilities. The primary instrumentation for the survey was
a Simrad EK60 split-beam scientific echosounder system utilizing five frequencies
(18, 38, 70, 120, and 200 kHz) and a Simrad ME70 multibeam echosounder, with the ME70
trigger slaved to the EK60 system. |