Mercury content of large pelagic fishes from the northern Gulf of Mexico

The waters of the northern Gulf of Mexico (nGOM) support valuable recreational fisheries with many species retained for consumption. Evidence of the link between fish consumption and elevated levels of mercury in human tissue continues to accumulate. An investigation of total mercury levels in large pelagic fishes from the nGOM was initiated in the summer of 2006. Blue marlin (Makaira nigricans), yellowfin tuna (Thunnus albacares), wahoo (Acanthocybium solandri) and dolphin (Coryphaena hippurus) were sampled at Mississippi docks during fishing tournaments. Fish tissue sampling protocols and analytical techniques (direct mercury analysis) followed those used in a synoptic survey of total mercury in recreational finfish conducted by the National Seafood Inspection Laboratory, NOAA Office of Sustainable Fisheries. There were significant positive relationships between size and mercury concentrations in yellow and blackfin tunas, wahoo, dolphin, little tunny, and king mackerel. Highest individual value for total mercury was found in blue marlin (9.630 ppm) with an mean (n = 6) concentration of 7.099 ppm.