by DPI Victoria
In July 2011, Fisheries Victoria, the University of Melbourne, Deakin University and the South Australian Research and Development Institute initiated a 3-year research project to determine the source of Victoria’s King George whiting population and the movement patterns of juvenile whiting among Victorian bays and inlets.
Variation in the chemistry of King George whiting otoliths is being used to determine the source population of Victorian whiting and the movement patterns of juvenile whiting among bays and inlets
Understanding the population structure of King George whiting in Victoria and how it relates to the South Australian whiting fishery will allow for optimal management of this important recreational and commercial species.
Previous research by Fisheries Victoria has indicated that:
• Spawning aggregations and young larvae are only found in South Australia
• The spawning source of whiting in Victorian bays and inlets is hundreds of kilometres to the west
• Whiting larvae can drift in the water column for 3-4 months allowing for large distances to be travelled.
The current research project will use two novel techniques:
• Otolith microchemistry: otoliths (earbones) in fish grow daily and absorb trace elements from the surrounding water. Trace elements are unique to specific water bodies, so we can determine if King George whiting from South Australia and Victoria were spawned or spent time in the same water body based on the trace metal variation in their otoliths. This technique will be used to determine the source population of Victorian whiting and the movement patterns of juvenile whiting among bays and inlets in Victoria.
Adult King George whiting harvested from Port Phillip Bay
• Genetics: microsatellite markers are small sequences in DNA that are inherited and can be used to determine family linkages. We will use microsatellite markers extracted from tissue to determine if there are genetic differences in the populations of whiting in South Australia and Victoria and among the bays and inlets in Victoria.
This research project is funded by the Fisheries Research and Development Corporation, the Victorian Department of Primary Industries and recreational fishing licence fees.