The Fish Department - Research

Genetics of Gemfish

The Gemfish, Rexea solandri in the family Gempylidae, has been one of the most important trawl fishes in south-east Australia, but is currently overfished. The species occurs at depths between 100 m and 800 m, around the southern two-thirds of Australia and New Zealand (view distribution map).

The genetics of the gemfish were studied to try to find out the number of breeding stocks, as each breeding stock should have a separate management plan. We identified two Australian stocks, based on electrophoresis of protein enzymes and analysis of DNA. The stock boundary is at the western end of Bass Strait, with few specimens from western Tasmania showing limited mixing. Our findings support a management plan to develop the western stock while the eastern stock recovers from overfishing. Clear separation of the eastern Australian stock from that of New Zealand was not shown, although a separate breeding area has now been identified in New Zealand. A small number of eastern larvae transported to New Zealand by currents would be enough to break down a clear genetic difference in the two populations. The genetic analyses were carried out in the Evolutionary Biology Unit of the Australian Museum.

Publications From This Research

Parin, N.V. & J.R. Paxton. 1990. Know your catch, Australia's east coast gemfish. Australian Fisheries. 49(5): suppl. 5pp.
Colgan, D.J., & J.R. Paxton. 1997. Biochemical genetics and recognition of a western stock of the common gemfish, Rexea solandri (Scombroidea: Gempylidae), in Australia. 48(2): Marine and Freshwater Research. 48(2): 103-118, 5 figs.

Dr John Paxton Page