Patterns of mercury and selenium in tissues and stomach contents of the dolphinfish Coryphaena hippurus from the SE Gulf of California, Mexico: Concentrations, biomagnification and dietary intake

Selenium and mercury were evaluated in tissues and stomachs of the dolphinfish Coryphaena hippurus from two sites in the Southeastern Gulf of California. Hg levels were consistently low and exhibited the following patterns: muscle (0.14 ± 0.01 μg/g wet weight) followed by kidney (0.12 ± 0.02 μg/g), liver (0.11 ± 0.01 μg/g), and gonads (0.04 ± 0.00 μg/g). The maximum of Se was found in the kidney (5.60 ± 0.40 μg/g) and the minimum in muscle (0.60 ± 0.01 μg/g). All the Se:Hg molar ratios were between 3.7 and 697.1, with the minimum in muscle and the highest in gonads. The results indicate a contrasting behavior biomagnification of Hg and Se; smaller fish (<80 cm FL) did not exhibit biomagnification, in contrast with larger fish (>90 cm FL: 100% for Hg; 65% for Se). These results appear to be related to different feeding habits and availability of prey.