Spatiotemporal variability in Atlantic sea scallop (Placopecten magellanicus) growth in the Northern Gulf of Maine

Simulation-based assessment tools coupled with large-scale and consistent monitoring efforts contribute to the overall success of the Atlantic sea scallop (Placopecten magellanicus; ASC) fishery on the North American east coast. However, data from the Northern Gulf of Maine (NGOM) are usually excluded from the assessment because limited monitoring effort and an overall lack of information regarding the growth of ASCs in this region have led to large uncertainty of fine-scale dynamics. The objectives of this study are to determine if ASC growth varies spatially and/or temporally across the NGOM and if the variation in growth can be explained in part by variability in bottom temperature and bottom salinity. To achieve these objectives, ASC shells have been continually collected through a partnership between the University of Maine and Maine Department of Marine Resources since 2006. Individualistic ASC length-at-age curves are developed to evaluate small and large scale spatio-temporal variabilities. In comparison to ASC growth on Georges Bank and in Southern New England, it appears that ASCs in the NGOM are growing at a similar rate yet have the potential to grow to a larger size. No clear spatio-temporal trends in ASC growth are identified in the NGOM. However, our analysis reveals that bottom temperature and bottom salinity may be influencing inter-annual variabilities and contribute to growth rate differences seen between locations and years. This may imply changes in ASC growth in the future with increasing warming in the Gulf of Maine.