Many fisheries benefit from pre-recruit indices of year-class strength that can be used to predict fishery fluctuations (eg. western rock lobster, snapper). The King George whiting fishery is particularly sensitive to recruit variability because the fishery is based almost entirely on one year-class of sub-adult fish. There is a need for a pre-recruit index that can be used to forecast the strength of recruitment to the fishery in future years. We propose to evaluate two possible indices; linkage with annual variation in climatological and physical oceanographic variables that influence larval transport, and, linkage with annual variation in habitat cover for King George whiting.
Final report
Catches of King George whiting in Victorian bays and inlets vary greatly from year to year. This research was aimed at finding out how much of this variation was due to the environment, and whether we could use measures of environmental variables to predict catches in the future. King George whiting spawn along the coast of Bass Strait in late autumn/winter and the small (2 to 20 mm) larvae drift in Bass Strait for three to five months before settling in shallow seagrass and algal habitats in bays and inlets. The juveniles grow within the bays and reach the minimum legal size limit by about 3 years of age. By the age of 5 years most whiting have moved out of the bay onto the coast where they live their adult lives. This means that the bay and inlet fishery is based on a very narrow age range of older juvenile (also known as subadult) fish. This life history means that environmental factors that influence growth and survival in the larval and juvenile stage could have a major impact on the catch.
