Scientists cast doubt on selected fishing

CANBERRA, Australia, May 19 (UPI) -- Australian scientists say a less selective approach to commercial fishing is needed to maintain the productivity of the world's marine ecosystems.

The study by Australia's Commonwealth Scientific and Industrial Research Organization was led by Shijie Zhou of CSIRO Wealth from Oceans Flagship.

Zhou said ecosystem-based fisheries management is broadly practiced as a means of reducing the impact of fishing on marine ecosystems while ensuring sustainable fisheries. The common view, he said, is that highly selective methods that catch only one or a few species above a certain size limit are more environmentally responsible.

But he said recent advances in fishery science and ecology suggest a selective approach might exacerbate, rather than reduce, the impact of fishing on both fisheries and marine ecosystems.

"The trade-off is lower exploitation levels on currently highly targeted species against better use of more parts of the ecosystem," he said. "Selective fishing alters biodiversity, which in turn changes ecosystem functioning and may affect fisheries production, hindering rather than helping to achieve the goals of (ecosystem-based fisheries management). These effects have been overshadowed to some extent by a focus on overharvesting".

Zhou added, "It is time to critically rethink traditional selective fishing approaches that might not protect ecosystems and fisheries as intended, but may in fact make them more vulnerable to large changes in structure and function."

The research appears in the Proceedings of the National Academy of Sciences.