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The dolphinfish (Coryphaena hippurus) is a globally distributed marine predator that supports one of the most important coastal fisheries along the Eastern Tropical Pacific (ETP), but its spatial movements in this area are poorly understood. Stable isotope values (δ13C and δ15N) of white muscle from dolphinfish (n = 220) captured at different locations across the ETP (i.e., Mexico, Costa Rica, Ecuador, Peru and oceanic areas) were normalized to copepod baseline stable isotope values to estimate dolphinfish trophic position, movements and population dispersal. Movement or residence patterns were inferred from the difference in δ15N values (Δ15Ndolphinfish‐copepod‰) between copepods and dolphinfish muscle. Baseline corrected isotope values (δ13Cdolphinfish‐copepod and δ15Ndolphinfish‐copepod) of dolphinfish muscle were used to estimate isotopic niche metrics and infer population dispersal across isoscapes. Values of δ13C and δ15N differed between juvenile and adult dolphinfish and across the ETP. Trophic position estimates ranged from 3.1 to 6.0 with a mean of 4.6. Adults and juveniles had similar trophic position estimates, whereas isotopic niche areas (SEA ‰2) of adults were greater relative to juveniles in every location. Adult dolphinfish showed "moderate movement by some individuals" in all locations based on Δ15Ndolphinfish‐copepod values, except for Costa Rica where adults were classified with "high degree of movement by some individuals" whereas juveniles showed "limited movement" in all areas except Mexico. Population dispersal based on Δ15Ndolphinfish‐copepod values showed "moderate" and "high" dispersal for adults and "no dispersal" for most juveniles, except for Mexico. This study provides insight into potential dolphinfish spatial mobility across an area of interest for multiple nations, which can help to improve stock assessments and management of the species. [ABSTRACT FROM AUTHOR]

Feeding habits and habitat use inform ecosystem-based management strategies for commercial fish species. A consumer's diet can be assessed through stomach content analysis (SCA), bulk stable isotope analysis (BSIA) and compound-specific stable isotope analysis of amino acids (CSIA-AA). Our research establishes the first approach combining these traditional and novel techniques to provide insight on the movements and trophic ecology of dolphinfish (Coryphaena hippurus) in the Mexican Central Pacific (MCP) during 2013. Dolphinfish SCA (n = 311), muscle δ15N and δ13C BSIA (n = 148), and δ15N CSIA-AA (n = 9) were performed to assess trophic and movement patterns. Diet was composed of 59 prey items. According to the Prey-Specific Index of Relative Importance, the main prey were Argonauta spp. (24%), Portunus xantusii (11%), Dosidicus gigas (7%), and Selar crumenophthalmus (7%). Diet differed between seasons and age class but not by sex. Trophic position did not change with body size based on SCA or SIA with average estimates of 3.5, 4.1, and 4.3 based on BSIA, CSIA, and SCA, respectively. Adult dolphinfish showed a shift in their isotopic niche; bulk δ15N values varied widely in adults (⁓ 10‰) suggesting movements through different isoscapes while juveniles had more constrained values consistent with residency within the regional isoscapes. These results were supported by differences in source amino acid δ15N mean values between juveniles (4.6‰) and adults (0.8‰). Our findings suggest that the MCP is a migration corridor for dolphinfish between foraging areas across the Eastern Tropical Pacific. [ABSTRACT FROM AUTHOR]