UW Aquatic & Fishery Sciences Quantitative Seminar

Bill Clark & Ray Webster

International Pacific Halibut Commission

An embarrassment of data: trying to reconcile tagging, survey, and assessment estimates of halibut abundance

Abstract

Mark-recapture data from a large ongoing experiment indicate higher levels of migration by halibut than previously thought, but the tagging data are extremely puzzling in some respects. Migration explains the differences we have seen between survey and assessment estimates of relative abundance in different parts of the northeast Pacific. It now appears that fishing mortality rates have been well above target in the eastern Gulf and well below in the west. Moving toward proportional harvest is proving difficult because it would entail a major shift in quota share among shareholders in the different regions.