Pressure is increasing for a network of marine reserves where fishing is banned. LOUISE THOMAS listens to the arguments.
Marine reserves in which fishing is banned have become a popular conservation cause.
Conservation Minister Sandra Lee wants 10 per cent of New Zealand's territorial waters given over to such reserves. Green Party leader Jeanette Fitzsimons is backing her but wants 20 per cent, saying more marine reserves will help maintain good fisheries.
Forest and Bird wants 20 per cent, and the World Wildlife Fund New Zealand and now the National Party says we must to do it for the sake of Sir Peter Blake.
While no one disputes that some marine reserves would be nice to have and are a good device to protect delicate marine ecosystems, some fisheries and marine scientists are decidedly uneasy about the crusade.
They fear that the concept of numerous networked marine reserves could harm New Zealand's fisheries.
Ms Fitzsimons wrote recently: "The international literature suggests that protecting 20 per cent of our marine area will maximise fishing potential in the other 80 per cent."
However, Seafood Industry Council policy manager Nici Gibbs says such research does not apply here.
"These types of arguments have arisen in countries where there is no quota management system. These places might need marine reserves to guard against unsustainable fisheries management where you have free open access and unlimited commercial fishing. This is not the case in New Zealand.
"I see the current drive for marine reserves to take up 10 or 20 per cent of our territorial waters as a slogan. It has no basis in any kind of ecological reality.
"If the issue is we want to protect certain marine ecosystems or we want to protect icon species, then fine, let's identify these and find the most appropriate tools, whether they are marine reserves or otherwise, not dictate arbitrary percentages of one type of management mechanism.
"I could argue that New Zealand's entire Economic Exclusion Zone is already protected by the Fisheries Act, with its focus on sustainability and restrictions on catches," says Nici Gibbs.
National Institute of Water and Atmospheric Research principal scientist Dave Gilbert agrees that the concept of marine reserves sustaining good fisheries is flawed.
He says removing even 10 per cent of New Zealand's territorial waters from the equation will result in increased catches being taken from the rest.
What is more, while some species will benefit locally from the lack of human interference, there is little scientific evidence that overall fish populations will benefit from the establishment of marine reserves.
"We've got an effective quota management system which already restricts catches. Commercial fishers don't generally exceed the total allowable catch because of the possible penalties, and also many of them don't want to ruin the resource.
"There certainly isn't a free-for-all going on where fishing areas just get thrashed, as happens in many countries where they don't have effective management systems."
Mr Gilbert argues that if extensive marine reserves are introduced into an already functioning sustainable system, they will force the catch to be taken from other places.
That will impose costs on the fishing industry. If fishing boats are banned from an area, they will have to venture farther out, using more fuel. The catch will still be the same and the fish population will remain roughly the same.
"While there might be more fish in the reserves there will be fewer in the remaining fishing grounds," Mr Gilbert says.
Nici Gibbs agrees: "If the Government is successful in locking up 10 per cent of New Zealand's fishing grounds, there will be significant implications for commercial, customary and recreational fishers.
"Given that most marine reserves will be near shore, this will really impact on paua and rock lobster fisheries which you could safely say are currently among our most environmentally sustainable fisheries anyway."
Proponents of marine reserves such as Bill Ballantine, from the Leigh Marine Reserve in Auckland, argue that reserves provide seed stocks of fish to replenish fisheries.
"In the sea, we are very ignorant of the way stocks relate to reproduction, even in the best-studied fisheries. The little we do know indicates large differences in juvenile recruitment from year to year even when stocks are constant.
"It would clearly be prudent to keep back from harvesting a significant amount of each stock. It would be sensible to make sure these breeding reserves were some of the best. It would be wise to have these untouched stocks spread about in different places. These reserves would then be like the food or seed you couldn't eat," Dr Ballantine wrote in a recent report.
However, Mr Gilbert says that the argument that marine reserves provide seed stock for fisheries is weak.
"The quota system in New Zealand has been set to ensure that fish levels stay well above the level where each stock can replenish itself.
"Even if something went wrong, like the total allowable catch level for a particular species was set too high and the stock gradually declined, we would notice this. The Ministry of Fisheries would immediately reduce the total allowable catch limit and the stock would begin to increase again."
He says fish have extremely high fertility. One fish can produce a million eggs. The evidence that large numbers of fish are needed to replenish a stock is weak and highly debatable.
What is needed are the right conditions. So what happens is that there are big variations in the numbers of young fish produced from year to year, or from decade to decade, depending on oceanic or climate conditions.
"The oceans are well used to large fluctuations in the abundances of species," says Mr Gilbert.
Department of Conservation marine protection policy analyst Jim Nicolson acknowledges the concerns of the fishing sector.
"But looking at mainland New Zealand, the fact is that at the moment there are only 16 marine reserves. This is 0.1 per cent of NZ's territorial waters in marine reserves, excluding the Kermadec Islands.
"Point one per cent is a pretty negligible amount. Even if we quadrupled this amount, it is still under 1 per cent. It is hard to see how this would impact on the fishing industry.
"I think there isn't a lot of disagreement that marine reserves are useful and that they do serve certain purposes.
"Certainly they are great for science, to study the sea and the relationships between a range of animals on a long-term basis, and there is a chunk of the population who want areas protected for their intrinsic value in the same way as national parks, but they are not perfect for day-to-day fisheries management."
Mr Nicolson says having marine reserves for every possible protection situation does not work.
The quota management system is needed to protect the populations of various fish species across the whole marine environment and this has to be weighed against having a viable fishing industry.
Mr Gilbert says the Government could not justify large areas of marine reserves for scientific purposes. "We can study some small areas, but the economic costs to the seafood industry of setting aside large areas would be considerable and we don't have the scientific resources to study them."
Mr Nicolson says the main issues that need resolving are where exactly marine reserves should be and what percentage of territorial waters should be given over to reserves without squeezing the fishing industry too hard.
"There are no right answers to these questions at the moment. By far the best way would be for some good integrated marine planning to occur on a national basis, which involves all these interests rather than them all competing."
Nici Gibbs agrees: "From the seafood industry's point of view it is not so much the question of marine reserves but the whole range of tools that you might make use of to achieve a whole range of different types of marine protection for a range of purposes.
"We don't see marine reserves as a fisheries management tool at all. We see the Fisheries Act as offering a range of tools that ensures fisheries are sustainable. As well as the quota management system, this act has a number of other environmental protection tools."