Variations in the Biological Characteristics of the Patagonian Scallop (Zygochlamys patagonica) Across the Argentine Shelf Break Front

ABSTRACT Oceanographic fronts and their associated physical processes create strong spatial patterns of food availability that may influence the metabolic processes of bivalves located within these areas. To investigate this prediction, we used mass-size relationships, condition indices, and carbon (C) and nitrogen (N) stable isotopes to evaluate how the biological characteristics of the Patagonian scallop (Zygochlamys patagonica) are influenced by the Shelf Break Front (SBF) and the surrounding chlorophyll a concentration (CSAT). Scallops from 2 transects across the front (38–39°S, 55–56°W, southwest Atlantic Ocean) were sampled with a nonselective dredge in October 2005. The results show that the SBF position, estimated from satellite-derived sea surface temperature, was more stable than the CSAT maximum concentrations. If muscle tissue is considered a better indicator of food shifts as previous studies indicate, scallops located far from the front have lower C isotopic signatures and C/N ratios than sc...