Abstract

Trophic relationships within marine food webs regulate energy transfer from primary producers to high level consumers, and changes in foraging patterns of consumers can influence ecosystem stability and resiliency (Bornatowski et al. 2018). Pelagic predators, such as common dolphinfish (Coryphaena hippurus), have high economic value but also influence the structure of coastal and offshore communities and associated food webs through top-down control (Collette et al. 2011). Stable isotope analysis, a widely used trophic ecology tool, can elucidate source(s) of organic matter supporting pelagic predators as well as their trophic position (Richards et al. 2020). In addition, regional variability in these dietary signatures may indicate broad foraging habits in trophic relationships and food web structure across regions or ocean basins. The purpose of the present study is to assess trophic relationships of the common dolphinfish at the ocean-basin scale using two common dietary markers: δ15N and δ13C. Common dolphinfish muscle biopsies were collected from the Gulf of Mexico (n = 52), Caribbean Sea (n = 26), Pacific Ocean (n = 20), and Atlantic Ocean (n = 45) (Figure 1). Biopsies were freeze dried, powdered, and tinned for δ15N and δ13C analysis at University of California - Davis Stable Isotope Facility.

PDF Preview