Total mercury, alkyl mercury and selenium concentrations in the muscle tissue of several species of pelagic sharks from northern Australian waters are reported. Mean mercury concentrations ranged between O .13 mg /kg for Carcharhinus brevipinna and 1. 94 mg/kg for C. amblyrhyn choides. Maximum values exceeded 1.5 mg/kg in nine of the species studied and the highest recorded concentration was 3.7 mg/kg for Sphyrna mokarran.

Mercury concentrations were highly dependent on the size of shark, a relationship that was adequately represented by the power function. Males of most of the species studied had significantly higher levels of mercury than females of similar size.

This report concludes investigations into the economic and biological viability of scallop culture in Tasmania. Research into spat settlement and ongrowing methods has continued from the 1970's and the current TFDA and FIRTA funded programmes (1980-84) have successfully cultured scallops to legal, marketable size. The purpose of this report is to examine the economic feasibility of a scallop farming venture based upon traditional methods of culture.