Spatial distribution of fish in and around offshore energy areas in southern New England

Offshore energy development is changing the seascape in the southern New England (US) region and this development may have impacts on the living marine resources managed by NOAA Fisheries. An active acoustic survey, conducted in late October/early November 2023, used a DriX-8 uncrewed surface vehicle (USV) to evaluate and map spatial and temporal distributions of fish in relation to four offshore wind energy areas. Sand lance (Ammodytes sp.) is an important prey species in the North Atlantic ecosystem, playing a vital role in energy transfer in the food chain, making them a cornerstones of these complex ecosystems. Utilizing wideband data (35–45 kHz and 90–145 kHz Kongsberg EK80), we generated echograms using Echoview software and python code. Target identification and discriminant analyses were used to separate echoes from schools of fish and sand lance based on their acoustic-frequency responses. Utilizing this backscatter, we were able to map sand lance distribution in and around offshore energy development areas in the southern New England region. Through this work, we found that active acoustic data acquisition using USVs pose a promising path for collecting biological data for resource and habitat assessment, particularly in areas where human-use dimensions may disrupt traditional sampling strategies. [Work supported by NOAA Ernest F. Hollings Scholarship Program.]