DISCRIMINATING POPULATIONS OF THE EASTERN KING PRAWN, PENAEUS-PLEBEJUS, FROM DIFFERENT ESTUARIES USING ICP-MS TRACE-ELEMENT ANALYSIS

ICP-MS is being used to determine if prawns, like some species of fish , possess an ''environmental imprint'' attained in their juvenile nurs ery habitats. Such an imprint could act as a naturally occurring tag a nd provide useful information on nursery grounds, migration patterns, and stock structure. Samples of juvenile eastern king prawns, Penaeus plebejus, from four different estuarine nursery areas several hundreds of kilometers apart were distinguished from one another using combina tions of the concentration of elements in their body tissues. Four dif ferent body tissues were used: eyes, hepatopancreas, abdominal muscle, and exoskeleton. Canonical-variate (discriminant) analyses showed tha t each of the four body tissues could be used to correctly classify th e samples with high (100%) predictability. The results, although helpf ul, should be treated with caution as they only provide a static and n arrow representation of the prawns' elemental profiles in space and ti me. Further experiments are in progress to determine if the prawns ret ain these differences through time in the wild and in the laboratory.