2025/08/04 by Nina R. Santos, Joseph A. Langan, Christopher Mayer +1 · 1 voice
Environmental Science · #Isotope Analysis in Ecology #Marine and fisheries research #Marine Bivalve and Aquaculture Studies
paper · doi:10.3354/meps14938
openalex publication_date 2025/08/04 · openalex created_date 2025/10/10 · openalex updated_date 2026/06/11
In the Northwest Atlantic Ocean, climate warming is driving new ecological interactions as temperate black sea bass Centropristis striata abundance increases in the southernmost extent of boreal Atlantic cod Gadus morhua . We examined dietary and trophic niche overlap of black sea bass (n = 69) and Atlantic cod (n = 67) in southern New England using stomach content analysis and bulk and compound-specific amino acid isotope analyses. Both species exhibited highly selective (Levins’ index: 0.17 ± 0.16) and overlapping (Morisita-Horn index: 0.4 ± 0.5) diets dominated by decapod crustaceans (frequency of occurrence: 82-89% of stomachs, total diet wet weight: 72-79%). Evidence of dietary selectivity for juvenile cancer crabs, like Jonah crab Cancer borealis , may constrain recruitment and increase vulnerability of the emerging Jonah crab fishery in southern New England to predation. Both species exhibited overlap in isotopic niche (Bayesian standard ellipse area overlap: 59 ± 19%) and baseline nitrogen isotope values (Atlantic cod: 7.5 ± 1.7‰; black sea bass: 7.7 ± 1.5‰), coupled with functionally identical trophic positions (Atlantic cod: 3.7 ± 0.4; black sea bass: 3.6 ± 0.2) that corroborate stomach content data, indicating that Atlantic cod and black sea bass were foraging on the same diets over relatively small ranges compared to cross-shelf isotope gradients. Our multi-metric foraging data suggest that the niche overlap between these 2 demersal predators has a variety of potential implications for their top-down control on the structure and function of southern New England ecosystems, as well as the management of fisheries that depend on them.