Trace elements in the otoliths of yellow-eye mullet ( Aldrichetta forsteri) as an aid to stock identification

Abstract

Concentrations of trace elements in the sagittal otoliths of yellow-eye mullet from three (1986) and four (1988) locations along the coast of southwestern Australia, including two neighbouring estuaries, were determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES). Canonical variate (discriminant) analyses of the elemental concentrations showed these to be specific to the location of capture of the fish, although, with the exception of Swan River samples, there was a considerable overlap of data points. There were substantial (and unexplained) differences in the potassium concentrations in samples taken in 1986 and 1988, but other aspects of the accumulation patterns appeared to persist through time. Populations of yellow-eye mullet in the Swan River might, therefore, be regarded as essentially separate for some fisheries management purposes, but the similarity in element accumulation patterns for the other locations suggested that further evidence would be required before they could be regarded as demographically isolated.