The 1989 Pacific west coast bottom trawl survey of groundfish resources: Estimates of distribution, abundance, and length and age composition

Abstract

The 1989 Alaska Fisheries Science Center west coast triennial bottom trawl survey was conducted to assess stocks of groundfish inhabiting the continental shelf waters off California, Oregon, and Washington. This was the fifth survey in a series to monitor long-term trends in the distribution and abundance of these groundfish populations.

In contrast to the preceeding triennial trawl surveys, the 1989 survey design shifted emphasis away from estimating rockfish abundance. Instead, the 1989 survey objectives emphasized assessing a broader range of groundfish species. The design also focused upon precisely estimating the near-bottom component of the Pacific hake (Merluccius productus) resource and juvenile (age 1+) sablefish (Anoplopoma fimbria), which inhabit waters shallower than 366 m. The survey extended 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 601 stations were occupied, of which 539 were successfully sampled. Catches included 121 groundfish species.

In this report, we document the survey design and the methods used, summarize the data collected, and report the results of our analyses of distribution, abundance, and biological parameters. Included are temperature data, catch composition, relative abundance, and species distribution information. Estimates of biomass, population numbers, and length and age composition are also presented.


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