The 1992 Pacific west coast bottom trawl survey of groundfish resources: Estimates of distribution, abundance, and length composition

Abstract

The 1992 Alaska Fisheries Science Center West Coast triennial bottom trawl survey was conducted to assess stocks of groundfish inhabiting the continental shelf waters off the coasts of California, Oregon, Washington, and British Columbia. This was the sixth survey in an ongoing series to monitor long-term trends in the distribution and abundance of these groundfish populations.

The objectives of the 1992 survey were similar to those of the 1989 survey; however, the survey design shifted emphasis away from estimating rockfish abundance, as had been the case in the early surveys (1977, 1980, 1983, and 1986), and instead emphasized assessing a broader range of grgundfish species. The design also focused upon precisely estimating the near-bottom component of the Pacific hake (Merluccius productus) and juvenile, (age 1+) sablefish (Anoplopoma fimbria) resource. The survey encompassed the coastal waters from Pt. Conception, California, to central Vancouver Island, British Columbia (34°30' - 49°40'N lat.), between the depths of 55 and 366 m. A total of 569 stations were occupied, of which 501 were successfully sampled. Catches included 135 different species.

Survey design and the methods used are described, the data collected are summarized, and the results of analyses of distribution, abundance, and biological parameters are presented. Data on water temperature, catch composition, relative abundance, and geographic distribution are reported. Estimates of biomass, population abundance, and length composition are also presented. Data appendices are located in a separate companion volume.