An ensemble high-resolution projection of changes in the future habitat of American lobster and sea scallop in the Northeast US continental shelf

Aim: To address the uncertainty associated with climate-driven biogeographical changes in commercial fisheries species through an ensemble species distribution modelling (SDM) approach. Location: Northeast US Continental Shelf Large Marine Ecosystem (NEUS-LME). Methods: We combined an ensemble SDM platform (BIOMOD 2) and a high-resolution global climate model (NOAA GFDL CM2.6) to quantify spatiotemporal changes in habitat of two commercially important species in the Northeast US Continental Shelf Large Marine Ecosystem (NEUS-LME); American lobster (Homarus americanus); and sea scallop (Placopecten magellanicus). An ensemble SDM was calibrated using multi-decadal fisheries-independent surveys (1984–2016). Statistically weighted species-specific ensemble SDM outputs were combined with 80 years of projected bottom temperature and salinity changes in response to a high greenhouse gas emissions scenario (an annual 1% increase in atmospheric CO₂). Results: Statistically significant changes (p <.05) in habitat suitability for both species were found over a large portion of the study area. Sea scallop undergoes a northward shift over the study period, while American lobster moves further offshore. The ensemble projections showed that several management zones were identified with increases and decreases in species-specific habitat. Uncertainty due to variations in ensemble member models was also found in the direction of change within each management zone. Main conclusions: This study provides ensemble estimates of climate-driven changes and associated uncertainties in the biogeography of two economically important species in the United States. Projected climate change in the NEUS-LME will pose management challenges, and our ensemble projections provide useful information for climate-ready management of commercial fisheries.