Fishy future written in the genes( The roadmap to the future of the gor...)

The roadmap to the future of the gorgeously-decorated fish which throng Australia's coral reefs and help earn the nation $5 billion a year from tourism may well be written in their genes.

Of particular importance may be to protect 'pioneer' fish populations which are able to re-colonise regions of reef devastated by global warming and other impacts or settle new areas as the corals move south, says Dr Line Bay of the ARC Centre of Excellence in Coral Reef Studies, James Cook University (JCU) and Australian Institute of Marine Science (AIMS).

Dr Bay and her colleagues Dr Julian Caley of AIMS and Prof Ross Crozier of the School of Marine and Tropical Biology, JCU have been studying the relationships among fishes across the Great Barrier Reef using genetic means to establish which populations are long-established and which seem to come and go in a pattern of local extinction and re-colonisation.

By studying the mitochondrial DNA of spiny damselfish collected from 15 reefs along 3 transects (lines) across the north, middle and south of the GBR, the researchers have been able to build up a 'history' of the damselfish's population.

"It's really interesting. We found, for example, that populations at the southern end of the Great Barrier Reef are 'younger' than those in the central or northern parts and have experienced larger population fluctuations. This suggests they undergo cycles of local extinction and re-settlement, which are nothing to do with human activity whereas the central and northern populations are far more stable."

Dr Bay says these fish populations that come and go at the edge of the Great Barrier Reef may represent the sort of natural pioneering that goes on at reef margins normally: however in times of extreme change such as global warming and acidifying oceans they take on fresh significance.

"It's about understanding how fish populations on separate reefs are connected to one another that
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