Active acoustic detection of fish and zooplankton along bathymetric features of the New York Bight
Abstract
The Hudson Canyon, located along the shelfbreak of the New York Bight (NYB), has been characterized as a “biological hotspot” that attracts organisms ranging from zooplankton to marine mammals. Since 2017, seasonal surveys have collected multifrequency acoustic backscatter data (38, 70, 120, and 200 kHz) and hydrographic measurements to investigate how bathymetric features, such as the continental shelf and submarine canyons, influence spatiotemporal distributions of marine organisms throughout the NYB. Relationships between overall biological backscatter (fish and zooplankton) and various oceanographic variables were evaluated using a hierarchical model. Fitted relationships were projected onto numerical ocean model outputs to explore how physical oceanographic features, such as the Mid-Atlantic Cold Pool (9C isotherm) and abrupt bathymetric changes, drive spatial variability in marine organisms. Combined biological backscatter was predominantly offshore in winter before shifting inshore during the summer, with hotspots predicted along the shelfbreak and Hudson Canyon throughout the year. The spatial extent of the cold pool displaced nearbottom fish offshore in spring and summer, concentrating fish backscatter between the shelfbreak front and the southern extent of the cold pool. These findings provide valuable insights into the role of physical features and oceanographic processes in shaping fish and zooplankton distributions throughout the NYB ecosystem.
