On the other hand, the Peggy Jo captured far more walleye pollock of all sizes than the Resolution did. These observations are not surprising given the lower vertical opening of the 400-mesh Eastern otter trawl, which is designed for maximum bottom contact, compared to the high opening Nor'eastern trawl with roller gear and the demersal distribution of flatfish and semipelagic distribution of pollock. While the experiment was successful in determining the relative differences between the two surveys in catchability of walleye pollock, Pacific cod, flathead sole, and arrowtooth flounder, the results indicate a large difference in the relative availability of pollock to each of the two survey configurations. Compounding the large difference in catch rates between the two gear types is an apparent size selectivity difference suggesting that juvenile pollock are not readily available to the lower opening 400-mesh Eastern trawl. Incorporating the pollock data collected by the two gear types into stock assessments for management purposes will require careful consideration.
Plans are already well under way for future cooperative efforts.
The AFSC would like to acknowledge the cooperation and teamwork demonstrated by the captains, crews, and scientists aboard each of the three vessels. Their commitment and enthusiasm were instrumental in meeting the study objectives. Particular thanks go to Captain Ron Kutchick of the Resolution whose intimate knowledge of the study area resulted in choosing tow sites that provided consistent catches for the major target species. Thanks also to Captain Brian Beaver and crew of the Peggy Jo and Captain Paul Desjardin and crew of the Pandalus for their skill and patience in executing the research plan.