Marine parks no answer to threats

Australia's marine environment is extraordinarily diverse, beautiful and needs to be protected for all Australians, now and into the future. This view is shared by most and it's the reason many prominent Australians have thrown their weight behind the current push for more marine parks in WA.

National parks are important for conserving nature on land and it seems logical the same approach would be appropriate for protecting our seas. Those calling for more marine parks also point to scientific research that supposedly supports the establishment of marine parks.

Much of this research has found what we'd expect - that when fishing is prohibited, some species of fish tend to become more numerous, grow older and become larger. And where serious overfishing has occurred, marine parks can also lead to changes in the abundance of some of the animals and plants that aren't fished, such as the recovery of seaweeds when fish predation reduces the numbers of grazing animals like urchins.

The increase in fish numbers on reefs inside no-take marine parks is often clear to anyone who has snorkelled in these areas. It's led to the assumption a total ban on fishing in so-called "sanctuary zones" provides a significant, or even complete, level of protection against known threats to the wider marine environment - threats such as pollution, introduced marine pests and climate change.

This raises a key and frequently overlooked question for the current debate over marine protected areas. Do they contribute in a meaningful and cost-effective way to wider coastal management?

Marine parks as they are being implemented in Australia predominantly provide protection from only one threat - fishing - and they do it only for small parts of the coast.

Is this an adequate or appropriate way to manage of our vital marine ecosystems? If we are seriously concerned about the marine environment, should we be more ambitious and aim to protect the wider coast and in so doing deal with all threats facing the marine environment?

Protecting the wider ecosystem rather than a patchwork of marine parks is all the more important when you consider the richness and range of marine species.

We don't even have names for many marine animals, let alone know their distribution, which means we run a serious risk of providing no protection to many species if marine parks are our conservation strategy of choice. So there's a moral obligation and sound scientific reasons to take a different approach to what's used on land.

Marine parks in the form being proclaimed in Australia are unable to protect the marine environment from the major threats of pollution, introduced marine pests, climate change and the specific threat of overfishing.

Pollution and introduced pests don't respect park boundaries. Any overfishing problems are just displaced from the area that is closed to the wider coast rather than being fixed by reducing the total amount of fish being harvested.

Though marine parks in Australia are officially intended for biodiversity conservation and are not about fisheries management, they are continually promoted by exaggerated claims that global and Australian science has demonstrated sanctuary zones can increase fish catches, improve fisheries value and generate rewarding fishing experiences in adjacent non-protected areas (for example, Meeuwig et al. in The West Australian, November 21, 2011).

This concept of marine parks increasing catches in areas nearby is called the "spillover benefit", something research has shown only occurs where serious overfishing exists. In other words where there is adequate fishery management, as is clearly the case in WA and more generally in Australia, it is misleading to espouse there will be a spillover benefit to a fishery.

Another exaggerated claim by the proponents of marine parks is that they will contribute to the "recruitment" of young creatures into surrounding areas, suggesting the current plight of the WA lobster fishery may have been avoided with more marine parks. This is misleading.

The WA lobster breeding stock indices are at near record highs, so it's highly unlikely the failure of recruitment was caused by reduced breeding stock.

In this context it is also important to consider the wider effects of excluding fishing from marine protected areas. Marine parks tend to displace catch to adjacent areas, which means the wider coast is fished even harder.

This displaced catch has been seen to tip fisheries into decline with all of the consequent ecosystem impacts. If breeding stock of western rock lobsters were a real issue then the only responsible approach would be to increase levels of breeding animals.

The best way to do this is to remove fewer lobsters each year by simply reducing the quota. Shuffling the location of fishing catches with marine parks really doesn't help.

This highlights another often held misconception - that terrestrial park management can or should be translated to the sea. Our oceans have not been subject to the same habitat alteration; no marine species have been hunted (fished) to extinction; fences don't exist in the ocean thus parks cannot be easily demarcated and managed against all impacts; and impacts don't respect marine park boundaries - animals and their eggs and larvae move in and out of the reserve, as do pollutants and marine pests.

What we need from government is a greater commitment to coastal zone management and, more specifically, a greater commitment to assess and manage marine threats at their source.

If fishing is a concern, we need better fisheries management across the whole of the State not just in a small percentage of the coast.

If pollution is a concern we need to regulate all sources, not just in a few protected areas.

To suggest marine parks will protect us against oil spills is ridiculous - they won't. Similarly one might question why we need no-take marine parks to reduce the threat of subsea mining.

Ensuring our marine environment is protected requires more critical thinking, a more rigorous examination of the available science and a balanced approach that deals with all threats in all places, not just fishing in a few marine parks.

Professor Colin Buxton is director of fisheries, aquaculture and coasts at the Institute for Marine and Antarctic Studies, University of Tasmania; Dr Caleb Gardner is the institute's fisheries program leader; and Professor Bob Kearney is an emeritus professor of fisheries, University of Canberra.