Mercury levels in selected bycatch fish species from industrial shrimp-trawl fishery in the SE Gulf of California.

Baseline Hg concentration in bycatch fish from the SE Gulf of California were determined in muscle and liver of 19 species. Levels of Hg in muscle were compared with legal limits of this element in national and international legislation. Considering all fish species, mean concentrations in liver (2.458±1.997 µg g⁻¹) were significantly higher (p<0.05) than in muscle (0.993±0.670 µg g⁻¹). The sequence of averaged Hg concentrations in most ichthyofauna was liver>muscle. Highest level of Hg in muscle (2.556 µg g⁻¹) and liver (7.515 µg g⁻¹) corresponded to Diapterus peruvianus and Ophioscion strabo, respectively. Considering muscle samples, none of the species had levels of Hg above the limit (1.0 µg g⁻¹ wet weight) in the Mexican legislation; with respect to the Japanese (0.4 µg g⁻¹ wet weight) and British (0.3 µg g⁻¹ wet weight) legislations, 26.3% and 31.6% of the species respectively, were above the corresponding limits.