A framework for assessing harvest strategy choice when considering multiple interacting fisheries and a changing environment: The example of eastern Bering Sea crab stocks

Abstract

Ecosystem Based Fisheries Management aims to broaden the set of factors included in assessments and management decision making but progress with implementation remains limited. We developed a framework that examines the consequences of temporal changes in temperature and ocean pH on yield and profit of multiple interacting stocks including eastern Bering Sea (EBS) snow, southern Tanner, and red king crab. Our analyses integrate experimental work on the effects of temperature and ocean pH on growth and survival of larval and juvenile crab and monitoring data from surveys, fishery landings, and at-sea observer programs. The impacts of future changes in temperature and ocean pH on early life history have effects that differ markedly among stocks, being most pessimistic for Bristol Bay red king crab and most optimistic for EBS snow crab. Our results highlight that harvest control rules that aim to maximize yield lead to lower profits than those that aim to maximize profit. Similarly, harvest control rules that aim to maximize profit lead to lower yields than those that aim to maximize yield, but differences are less pronounced. Maximizing profits has conservation benefits, especially when the implemented harvest control rule reduces fishing mortality if population biomass is below a threshold level.