Australia’s brand-new marine park proposal has great historic precedent. For hundreds of years, ocean managers have found that reducing fishing can repair fish stocks and benefit not just ocean species, but surrounding fishing industries.

Fixed Tuna traps, catching blue fin tuna in their migration into the Mediterranean, have a thousand-year tradition in the Mediterranean. The highest reported catches were reported in 1568, when two traps reported catches of 14,000 and 7,000 tuna each. But there were very low catches between 1700 and 1730. The King of Spain, alarmed by the decline, commissioned an inquiry. It recommended a three year no-take moratorium and the release of female blue-fin tuna. Soon after, the catches recovered¹.

The two great wars in the 20th Century, when fishing almost stopped over large areas of the European seas, provided ample evidence that a moratorium in fisheries lead to rapid rebuilding of robust fish stocks. Closing areas to fish extraction is a compelling tool to restore depleted fish stocks.

The Atlantic Cod stock in Georges Bank, one of the largest fish stocks in the ocean, collapsed in the late 1980s. The Department of Fisheries and Oceans kept providing financial incentives to build cod fishing boats and processing plants, despite warnings of imminent collapse. The Canadian cod collapse had devastating social and political consequences extending over two decades. Twenty years after the 1993 no-take moratorium was established, there are now, for the first time, encouraging signs of recovery of the Canadian cod stock.

Based on available evidence, the World Summit on Sustainable Development in 2002 called for the establishment of marine protected areas consistent with international laws and based on scientific information, including representative networks by 2012. The Commonwealth has just delivered on this commitment: Environment Minister Tony Burke has created the largest network of marine protected areas in the world. With 3.1 million square kilometers, this network will expand four-fold the current protected area and will exceed the ocean area protected globally outside Australia. Hence, the area protected by Australia is bigger than all other protected areas elsewhere that together add to about 2 million square kilometers.

The Commonwealth plan includes three types of marine areas. These are designated by the International Union for Conservation of Nature (IUCN) into categories II, IV and VI. Category II, Marine National Parks, are large natural areas set aside to protect large-scale ecological processes and elements, with environmentally and culturally compatible spiritual, scientific, educational, recreational and visitor opportunities. Category IV areas, Habitat Protection Zones, are designed to maintain, conserve and restore species and habitats. Category VI, Multiple Use Zones, are designated to protect natural ecosystems and use natural resources sustainably, when conservation and sustainable use can be mutually beneficial.

Category II excludes commercial and recreational fishing, Category IV allows forms of commercial and recreational fishing that are compatible with the specific target species and habitats to protect, and Category VI is compatible with most uses.

Hence, the network has multiple goals. It builds additional resistance and resilience for fish stocks, protects fragile and critical habitats – such as shallow and deep coral reefs, seagrass meadows, kelp beds, shoals, and submarine platforms – and conserves the wealth of marine biodiversity in Australia’s waters.

Marine reserves can actually benefit adjacent fisheries. Adults and juveniles can emigrate across borders, and export eggs and larvae. This “spillover” should be welcomed by fishers. But marine reserves remain controversial. Critics contend they should not be implemented on a larger scale until more and stronger experimental proof of their efficacy is available. Fishers worry that reducing fishing grounds will decrease catches. They are also sceptical of whether people will comply with closed-area regulations. You will have heard all of these arguments since Minister Burke’s announcement.

However, a call for “more evidence” cannot be a perpetual scapegoat to adopt a precautionary approach to marine conservation. Indeed, a review published already 10 years ago reported increase in commercial fish abundance or catch per unit effort between 5 and 68 fold associated with marine reserves, with a tendency for fish size to increase as well. Evidence available shows a consistent tendency for the benefits of marine reserves to develop within two to five years of establishment and to continue to build for decades, including improved commercial fisheries in the periphery of the MPAs.

So how much marine area is being “locked up”? Two-thirds of Australia’s marine economic exclusive zone remains open to all uses. It is a vast expanse of ocean that, properly managed, should be able to deliver the wealth Australia expects and needs from the ocean.

Since my arrival to Australia a year ago I have been very impressed with the skills and competence of state-based fisheries managers. They correctly take pride in that Australia’s fisheries are the best-managed fisheries in the world. I concur.

However, in a world of change, fisheries managers cannot fully control the fate of fish. For instance, in a paper now in press in Global Ecology and Biogeography, my colleagues and I demonstrate a very large increase in larval fish mortality as a result of increased UVB radiation over the southern hemisphere. Global pressures, including anthropogenic global change, and natural variability, including climatic oscillations, can lead to failure of the best fisheries models available. Natural variability, indirect anthropogenic pressures and both commercial and recreational fisheries can align in a perfect storm, with catastrophic consequences for fish stocks. Evidence indicates that, once collapsed, fish stocks may take decades to recover.

A network of marine parks provides a buffer against such “perfect storms”. It provides a safe and stable operating environment for all: conservationists, fishers – both commercial and recreational – and oil and gas industry.

The creation of the largest network of marine reserves is a game changing initiative of profound consequences. So much is at stake, as a model for a sustainable ocean for the world, that the Commonwealth must take all possible steps to ensure success. This must include:

• generosity with those affected

• willingness to listen closely to the critics of this network, who often have legitimate insights, and a commitment to spare no efforts to bring them on board

• the humbleness required to acknowledge the limitations of the science and the associated uncertainties

• a monitoring plan which will rigorously audit whether the network will achieve the desired outcomes.

At Rio +20 next week, the Australian delegation can proudly look their counterparts in the eye. If Australians, a society of relatively-wealthy, informed and responsible citizens, cannot lead the world in taking this game changing step, who can?

References

1. Duarte, C.M. 2010. Ocean: The secret of planet Earth. CSIC and La Catarate, Madrid, Spain. [in spanish]