SS1.02 Geochemical Tracers in Calcified Structures: Implications for Fisheries Research
Date: Tuesday, June 11, 2002
Time: 2:45:00 PM
Location: Carson A
 
GillandersBM, University of Adelaide, Adelaide, Australia, bronwyn.gillanders@adelaide.edu.au
 
DETERMINING THE SPATIAL EXTENT OF CONNECTIVITY BETWEEN JUVENILE AND ADULT FISH POPULATIONS
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Do adults remain near their natal reefs? The elemental concentration of the otoliths of juvenile snapper (Sparidae) differed among groups of estuaries suggesting that the nursery or natal estuary of adult fish could be determined. Adult fish from the commercial fishery were then collected and fish with birth years matching the juvenile fish selected for microchemical analysis to determine their natal estuary. Juvenile fish from different regions could be distinguished with a high degree of accuracy. Using the juvenile signatures 2-year old adult fish caught as part of the snapper fishery in the Sydney region were assigned to their natal estuaries. The majority (89%) of adult fish had estuaries in the vicinity of Sydney as their natal estuaries. After taking into account the variability in the estimated proportions, all fish may have recruited to Sydney estuaries suggesting that adults on reefs outside estuaries have come from the estuaries closest to them with little transfer from other estuaries. Whether similar patterns are found for other regions and age classes will be discussed.