MERCURY CONCENTRATIONS IN STOMACH CONTENTS AND MUSCLE OF 5 FISH SPECIES FROM THE NORTH-EAST COAST OF ENGLAND

Mercury concentrations in stomach contents and muscle tissue are reported for five fish species: herring (Clupea harengus), whiting (Merlangius merlangus), roker (Raja clavata), plaice (Pleuronectes platessa) and dab (Limanda limanda) collected in summer 1992 off the mouth of the River Tyne, North East England. Median muscle mercury concentrations in the area increase in the order plaice < herring < roker < dab < whiting. Absolute mercury concentrations and muscle mercury-length relationships indicate that the environmental availability of mercury in the study area is low. Stomach contents were recovered from dab, plaice and roker only. Median mercury concentrations in stomach contents increased in the order plaice < roker < dab. The variability of the ratio (muscle mercury/stomach content mercury) has been examined for these three species. In dab the variation is relatively low (39.7% RSD), whereas in plaice and roker it is considerably higher (128.4% and 184.6%, respectively). If stomach content mercury concentrations accurately reflect local mercury availability then dab muscle tissue would make a more reliable availability index than muscle tissue of plaice or roker.