Anomalous behavior of trace element magnesium in fish tissues

Six fish species were collected: summer trout (Salmo alar), rock fish (Roccus lineatus), pink snapper (Lutianus ava), croaker (Stellifer lancelatus), sheepshead (Diplodus holbrooki) and spanish mackeral (Scomberomorus maculatus). Seven trace elements were determined by flame atomic absorption spectrophotometry. The results indicate that the trace elements iron, copper, zinc, mercury, chromium, and nickel show higher levels in the livers than in the flesh of all the six fish species. Surprisingly, magnesium concentration levels were consistently higher in flesh than in the livers of all six fish species.