EFFECTS OF TRAWL SAMPLING VARIABILITY ON PRECISION OF ACOUSTIC ABUNDANCE ESTIMATES OF GADOIDS FROM THE BARENTS-SEA AND THE GULF OF ALASKA

The quality of acoustic estimates of fish abundance is dependent on th e quality of the biological information that provides the basis for de termining target size, species composition and acoustic target strengt h distribution. Information on biological characteristics of acoustic targets is usually obtained from trawl samples. In this paper we analy se the effects of trawl sampling variability on estimates of gadoid st ock abundance in two areas where behavioural characteristics of the ta rget species differ. The analyses demonstrate the sensitivity of abund ance estimates to trawl sampling. Improved procedures for allocation o f trawl sample information to acoustic survey results are discussed.