Marine Protected Areas boost shark numbers

By Lydia Hales & Carolyn Barry 12 February 2014
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Large, isolated and well-established MPAs boost shark numbers, says study.

A COMPREHENSIVE STUDY of the world’s marine protected areas has revealed that large, established and well-enforced non-take zones are home to 14 times more sharks and much more sea life than commercial fishing areas.

However, some of the marine protected areas (MPAs) – typically those near fishing zones – were barely discernible from non-protected areas, in terms of the number and type of marine life.

The international study, led by Professor Graham Edgar of the Institute for Marine and Antarctic Studies at the University of Tasmania, looked at 87 MPAs, across 40 countries. By studying such a large sample, the researchers were able to determine a set of factors that contributed to the success or failure of a protected area.

A successful MPA typically had five features: no-take zone, well-enforced, over 10 years old, over 100km2, and isolated by sand or deep water.

“It is these kinds of MPAs that we need to create and at the same time retrofit the existing MPAs that are unlikely to ever reach their conservation goals”, Graham said in a statement.

Marine Protected Areas affected by overfishing

Almost two-thirds of the MPAs, however, had two or fewer features and were deemed to be “paper parks”, the study says – meaning they’re only token protected regions.

“We found little difference between fishes living in most MPAs and those in nearby fished areas, indicating that many MPAs are not achieving desired conservation outcomes,” Graham said.

In zones that allow fishing the outlook is dismal. The study, published last week in Nature, reported a large drop in fish numbers in un-protected areas: a 63 per cent decline overall, with 80 per cent of large fish, 93 per cent of sharks, 84 per cent of groupers and 85 per cent of jacks.

The picture is complex, Graham says. “What we do know is that numbers of many Australian marine species have collapsed since European settlement, including some that have disappeared. At present, coastal zoning maps are confusing, with the few conservation gems hidden amongst protected areas that are ineffective because of inadequate regulations or poor enforcement”.

MPA study helped by recreational divers

The amount of field data collected was “quite a quantum leap”, Graham says, and wouldn’t have been possible without the help of more than 100 skilled recreational SCUBA divers who were trained to collect data.

Graham says the study of this size would not have been possible had it not been for the volunteer divers.

Marine scientist Nick Graham from James Cook University says one of the most significant aspects of the work is the sheer scale of the dataset, which has allowed researchers not only to pin down the key features of successful areas, but specify measurements involved in these features.

Nick says the study highlights a need to carefully design and govern new and existing MPAs for them to be successful, with a focus on maximising the key features of successful areas.

But since most of the ocean is not protected and fished regions are faring poorly, there’s a “need to do a much better job of managing the wider seascape,” Nick says – for example by changing the types of fishing equipment and the way they are used.