Developing a framework to estimate dynamic reference points for American lobster using a thermally explicit spawning stock biomass/recruitment relationship

Abstract

Management of marine species often relies on biological reference points (BRPs): threshold and target indicators that trigger management actions. These BRPs are usually based on the biology of the species and rarely consider environmental effects. Under climate change, this is problematic as many biological/physiological relationships are assumed temporally static. This spurious assumption can lead to inaccurate management practices. To combat this problem, recent research highlights the importance of developing temporally dynamic BRPs. This paper sees the development of a dynamic BRP calculator to inform management of levels of spawning biomass necessary to sustain the desired future levels of recruitment given forecasted climate scenarios. We test this calculator on American lobster ( Homarus americanus) of the Gulf of Maine and Georges Bank. Results for lobster indicate a temperature-driven, but complex, spawning biomass/recruitment relationship. Increased warming scenarios appear to yield overall higher recruitment per spawning biomass and dynamic BRPs calculated under these scenarios reveal that smaller population levels can sustain management-desired recruitment levels. This study highlights the importance of developing dynamic BRPs for fisheries management in a changing environment.