Variation of toxaphene indicator compounds in fish from single fishing grounds: Conclusions for sampling

The levels of three toxaphene indicator compounds were determined in indivi dual lots of herring, redfish, Greenland halibut and farmed salmon. Concent ration levels of the three marine fish species were characterised by a righ t-skewed frequency distribution whereas residue concentrations in farmed sa lmon were normally distributed. The toxaphene concentrations in the edible part of redfish, herring and Greenland halibut were found to be positively correlated to the sizes and thus to age. As results show, for representative sampling of a landed catch, not more th an 10 individual fishes from typical size classes of a lot are necessary fo r a pooled sample. (C) 1999 Elsevier Science Ltd. All rights reserved.