Otolith chemistry of juvenile snapper Pagrus auratus in Victorian waters: natural chemical tags and their temporal variation

摘要: Determining contributions of juveniles from different areas to adult populations is diffi- cult using traditional methods such as manual tagging and recapture. Environmental variation can, however, produce natural chemical tags in the otoliths juvenile fish. Spatial otolith chemistry (Ba, Sr, Mn) age 0+ snapper collected inlets along coast Victoria, south- eastern Australia, enabled characterisation for specific areas. In particular, a tag based largely on high Ba levels was largest area most important fishery, Port Phillip Bay. This accurate discrimination between this bay (98 85%) other Victorian nursery 2000 2001 year classes, respec- tively. Differences classification accuracy these classes were due lower some sites within Bay 2001. Variation adjacent sampling months during recruitment period, although significant, did not confound spa- tial inlets. Likewise, while greater than months, greatly spatial discrimination. Comparisons across 5 over 9 yr period Bay, how- ever, showed substantial differences elemental driven by Sr levels, whereas between-month differ- ences Mn variation. Future classifications adults will require characterised same class(es) being classified. Small-scale (mo) temporal mismatches class should influence with which are classified origins.