Handfish Steps Back From Brink Of Extinction

January 21, 1998

The tiny spotted handfish, the first Australian marine fish listed as endangered under the Federal Endangered Species Protection Act, may escape extinction as a result of successful breeding trials and research into its biology.

"We believe we now have the techniques to proceed with developing a larger-scale breeding program for this and other related handfish species if required," said Barry Bruce, a biologist at CSIRO’s Division of Marine Research in Hobart.

"The next step is to develop a plan to guarantee the recovery of this species," he said.

Mr Bruce, who leads the Environment Australia Commonwealth Endangered Species Program and CSIRO-funded research project, said the breeding results are an especially significant milestone in the International Year of the Ocean.

Mr Bruce, and fellow researcher Mark Green, have successfully bred 35 baby fish from two adult pairs at the Tasmanian Department of Primary Industry and Fisheries Aquaculture facilities at Taroona.

The Tasmanian Departments of Primary Industry and Fisheries, and Environment and Land Management, the Tasmanian Conservation Trust and the University of Tasmania, are supporting the project.

Ironically, the spotted handfish, which grows to only 150mm in length as a mature adult, was one of the first Australian marine fish collected in the late 1790’s and was first described in 1804.

Noted for its superb colouring and its tendency to ‘walk’ over the bottom on leg-like fins rather than swim, the spotted handfish is found only in the lower Derwent Estuary and adjoining bays and channels.

Mr Bruce said the species had been protected under State Fisheries Legislation since 1995 and was listed under the Federal Endangered Species Act in 1996. Although common throughout its range prior to the mid 1980s, it has since declined in both distribution and abundance and is considered in danger of extinction.

The causes of its decline are not understood, although one of the contributing factors being investigated is the spread of the introduced northern Pacific Seastar throughout the Derwent Estuary.

This may be as a result of starfish feeding on egg masses or disturbing seabed communities. However, habitat modification through urban, rural and industrial development of the Derwent system are other possible causes.

Spotted handfish have a low breeding capacity, the female laying only 80-100 very large eggs which are held together by threads and generally attached to the seafloor.

The female guards the egg mass which takes 2-3 months to hatch and is thus highly susceptible to disturbance or predators.

Mr Bruce said the research team had, for the first time, been able to produce the right conditions for spawning and rearing of juvenile fish in tanks.

Before the research began two-years ago, very little was known about the handfish or even if any remained. The research involved surveys to locate remnants of the former population in the Derwent Estuary, monitoring these colonies, and the study of the biology and habitat of the fish.

"Although there are still many gaps in our understanding of the species and what affects them, the information we now have gives us a firmer basis to develop a plan for the recovery of the species" Mr Bruce says.

CSIRO Australia

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