Dynamic oceanographic influences on summer flounder (Paralicthys dentatus) abundances and distributions off coastal New Jersey

The Mid-Atlantic Bight (MAB) is a dynamic ocean region on the East Coast, USA with strong seasonal cycles, high interannual variability, and significant large-scale oceanographic shifts due to climate change. The MAB is critical habitat to many commercial and recreational fish species, including summer flounder (Paralichthys dentatus). Employing the New Jersey Department of Environmental Protection’s Ocean Stock Assessment Program, a unique 30-year nearshore dataset that captures seasonal to decadal variability, and generalized additive models, we investigate how the dynamic thermal environment of the MAB influences species abundance and distribution, with summer flounder as a test species. From our model, we observed distinct seasonal and decadal peaks in catch per unit effort (CPUE): 1) Spring (April in mid-1990s to 2010s), and 2) Summer (August in mid-1990s to early 2000s). Results of this study suggest that these CPUE peaks are often aligned with spatiotemporal shifts in bottom temperature, salinity, and stratification. To further explore these patterns, we examined the spatial differences in CPUE, bottom temperature and salinity, and stratification for two peak CPUE seasons highlighted by the model over decades. The oceanographic spatial patterns suggest that the fish may be responding to environmental changes in time; however, other factors, such as management regulations and fishing pressure, beyond the oceanography are also influencing CPUE.