Live reef fish trade decimating fish populations


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The live reef fish trade in northern Borneo has a severe impact on coral reef fish populations, according to the results of a new study.

Scientists from Cambridge University provided evidence to suggest that the live reef fish trade (LRFT) causes exponential declines in both the total catch and relative abundance of several coral reef fish species.

Helen Scales, Andrew Bamford and Andrea Manica quantified the local impacts of the LRFT after collecting data from three LRFT traders in northern Borneo over a period of several years.

Their findings, which are reported in the latest issue of Proceedings of the Royal Society B, show that total monthly catch and relative abundance (catch per unit effort) declined significantly in several species.

Live reef fish tradeThe live reef fish trade exploits brightly coloured coral reef fishes, such as groupers, snappers and wrasses, to supply luxury seafood restaurants, mainly in Hong Kong and mainland China.

Customers can observe colourful fish in aquaria and choose the one they wish to dine upon.

The authors say that the species targeted are inherently vulnerable to overexploitation because they grow slowly and mature late in life.

Exploitation by the LRFT saw most valuable species, the Napolean wrasse, Cheilinus undulatus, decline in catch size by 98%, with a 78% drop in relative abundance over eight years.

The catch of Blue-lined groupers, Plectropomus oligocanthus, dropped by 99% while relative abundance fell by 81% over eight years.

Epinephalus groupers, which are similarly long-lived, saw catches decline by 89% and relative abundance drop by 32% over the same period.

Rapid changeThe authors said that the declines in catch and relative abundance were severe, rapid, species-specific and took place in the first two to four years following the species' exploitation for the LRFT.

They claim that the results represent the first quantitative evidence indicating the severe impacts that the LRFT has upon reef fishes.

The authors concluded: "These declines took place in under a decade and are especially worrying given the mobile nature of the Kudat fishing fleet, since it is probable that vessels shifted range when nearby populations became depleted, thus maintaining catch rates for longer.

"Our data, together with global boom-and-bust trends in the trade, are a stark warning that similar collapses may be expected throughout the LRFT and in other high-value wildlife trades, but without longterm datasets these trends may go undetected."

For more information see the paper: Scales H, Bamford A and A Manica (2007) - Impacts of the live reef fish trade on populations of coral reef fish off northern Borneo. Proc. R. Soc. B. (2007) 274, 989-994.