(175) Fish Tales.
RANALDI, Melinda1, GAGNON, Marthe Monique*,1, WATLING, John1, WAKEFIELD, Corey1, 1 Curtin University of Technology, PERTH, Western Australia, AUSTRALIA
ABSTRACT- Pink snapper (Pagrus auratus) as well as being a long-lived, and highly prized, Australian commercial demersal reef fish is one of the most frequently line-caught recreational species. The pink snapper stocks aggregate in estuaries each year to perform spawning activities. Estuaries are often both the sites of intense anthropogenic activity and recipients of significant levels of industrial effluent. Consequently, fish frequenting these estuaries can be exposed to increased levels of xenobiotics and may deposit bioavailable pollutants on the growing edge of the otolith. This process can result in the contaminant being incorporated into the matrix of the otolith. Continuous analysis Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) is used to provide elemental distribution data of sections across the otolith, from the centre to the edge, to reveal the record of exposure to contamination of the fish from birth to death. The otolith metal content of adult fish collected in the chronically contaminated Cockburn Sound (Perth) is compared to the content in the otoliths of Shark Bay pink snapper, where heavy metal contamination is virtually non-existent. The spatial resolution of the LA-ICP-MS system, with 800 readings per mm of otolith, provides a level of definition and spatial (time) resolution never before possible to achieve. The resulting data has facilitated an identification of the history of bioavailable contamination in urban estuaries, as well as an indication of the fish yearly migration patterns and a means to delineate individual stocks.
Key words: LA-ICP-MS, otolith microchemistry, contamination history, metals