A fine collection of fish

By Rebecca Priestley In Science

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16th June, 2012 1 comment

Marti Anderson carrying out annual marine biodiversity survey

At the 1992 Earth Summit, New Zealand signed the Convention on Biological Diversity, committing us to protecting at least 10% of our coastal and marine territory by 2020. So how are we doing? Marine reserves protect only 0.3% of our exclusive economic zone (EEZ) – or 7% of our territorial sea – and almost all are around remote island groups like the Kermadec, Auckland and Antipodes islands. The reserves around New Zealand’s main islands comprise “an absolutely minuscule area”, says Chris Howe from WWF New Zealand.

WWF made headlines last month when its report on New Zealand’s environmental record since 1992 charged us with completely failing to meet the promises made at the Earth Summit. Howe says marine protection is an area in which we’ve performed abysmally. This month, a New Zealand delegation heads to the Rio+20 follow-up event, where protection of the marine environment will be on the agenda. Perhaps it’s time we took notice of research by people like Massey University’s Marti Anderson, a marine biologist and professor of statistics, that shows marine reserves really work. On her own dive trips – to reserves like Leigh, Hahei and Tawharanui – Anderson has observed some of the well-documented immediate effects of marine reserves, including “really large increases in the abundances and sizes of things that are otherwise targeted by fishers: species like snapper, blue cod and rock lobster”.

A recent study by Anderson’s PhD student Adam Smith revealed snapper populations inside the reserves have increased by as much as 17 times. At the same time, says Anderson, the natural system is re-established. “Snapper eat kina, and kina eat kelp. So where you have large snapper roaming around that are eating the kina, the kina populations are kept under control and the kelp forests flourish because they’re not being mown down by the sea urchins. And the kelp forest is something that supports a huge diversity of life: crustaceans, worms, molluscs, sponges, hydrozoans – more than 350 different species.”

But the benefits aren’t just for recreational divers, says Anderson. Marine reserves can be win-win – the Hahei Marine Reserve, which Anderson has been studying for 12 years, not only attracts divers and snorkellers, but “the lobster fishermen have very strategically placed all their pots right along the edge of the marine reserve and they get fantastic catches”. New research on the effectiveness of reserves along the Great Barrier Reef, just published in Current Biology, confirms that reserve networks benefit conservation and fisheries. Although marine reserves account for just over a quarter of the reef’s area, they produce about half the juveniles that end up in either local fisheries or the reserves.

Anderson and WWF agree it would be good to aim to protect 30% of New Zealand’s marine territory. “An inclusive stakeholder process should be run to decide where the protected areas should be,” says Howe. But he notes that scientists have already identified areas of the greatest marine biodiversity, and WWF considers some locations – such as the Maui’s dolphin habitat and the EEZ around the Kermadecs – so important they should be protected immediately. And would there be flow-on benefits to commercial fishers?

“My prediction is that if we put in a network of marine reserves, the overall productivity of the system and our ability to exploit the resources outside of those areas would go up,” says Anderson. But “the onus always seems to be on us to demonstrate that marine reserves are beneficial, but I’ve never seen anyone put forward the counterargument – we have never ever seen a fisheries collapse because someone has put a marine reserve in”.

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16th June, 2012 1 comment

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One Response to “A fine collection of fish”

  1. anhsmith Jun 26 2012, 11:43am

    I think it is important to mention that the study found *legally sized* snapper to be around 17 times as numerous in a marine reserve, when compared to outside the reserve. The legal size is 17 cm fork length for recreational fishing. There is a big difference between 17x as many snapper and 17x as many legally sized snapper.
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