Multi-scale quantification of the effects of temperature on size at maturity in the American lobster (Homarus americanus)

Abstract

Like most ectothermic species, American lobster growing in warmer environments mature at smaller sizes. A formal quantification of this pattern at multiple spatiotemporal scales has not been developed, impeding the development of tools to predict the impacts of climate change on American lobster life-history and fishery. In this study, data from sea sampling programs from southern New England to the Bay of Fundy are used to estimate female lobster size at maturity, and to quantify the effects of water temperature on maturity at three spatial scales: i) regional (∼1000km), ii) stock (100skm), and iii) Statistical Area (10skm). Resultsshow that female lobsters living in warmer waters mature at smaller sizes and that other factors, likely fishing, also contributed to the observed decrease in length at 50% maturity. This study suggests that adaptive management plans need to consider temperature-induced trends in size at maturity to ensure sustainability of the valuable American lobster fisheries. Additionally, this study provides a maturity function for use in models that aim to project effects of climate change on American lobster populations and fisheries dynamics.