Since 1980, I have been recommending that 10% of all New Zealand seas be made into non-extractive marine reserves. One tenth of all marine habitats in all regions of the country. Why the figure of 10%? is this just a nice round number? No, it has a reasonable basis in experience and principle.
One tenth has a long traditional use as a figure that signals importance without serious hurt. In religous tithes, insurance premiums, business contingencies and other fields, one tenth is commonly used to indicate that the point to be covered is of great importance and must be provided for, but that precise measurements of necessity are not possible.
The 10% contrasts with the 90% for exploitation, for fishing, aquaculture, and other extractive or intensive uses, and clearly recognises the importance of these uses. We are not trying to change direction, we are trying to support, insure, and protect the system that allows " business as usual".
There is virtually no direct marine experience for a reservation amount, but on land in New Zealand, much more than 10% reservation from extractive and intensive use has been found worthwhile. Land reserves comprise between 20-30% of the total area of New Zealand. 10% is therefore a conservative figure for our seas.
Natural variation in marine resources (such as fishable stocks) is known to exceed one tenth. The year to year variation, due to natural changes in weather and other uncontrollable factors, is generally much more than 10%. The implications of this are many and subtle, but it means that any arrangements made for using these resources must have at least a 10% safety factor built into them, if they are to be sustainable. Because of economic and political pressures, it is very difficult to build a safety factor into actual extraction quotas, indeed they are often set with a risk factor of damage or collapse. This may be acceptable to the particular industry and the immediate economic conditions. We need a separate and additional system to provide for the overall public interest in long-term sustainability.
It can be questioned why we need a figure at all for marine reservation. Would it not be possible to operate step-by-step, without setting any general aim point? Well this is what we have been doing until now. The results have been 3 marine reserves after 25 years of step-by-step discussion, while the resource base is increasingly pressured and shows clear signs of general degradation and particular losses.
There are two reasons for setting a clear aim for marine reservation. One is to reassure those who might be worried about "where will it all end?". It is an amazing fact that even when the first tiny marine reserve was proposed some people leapt up and started crying, "We must make a stand before they lock it all up!" Even if this is merely a slogan produced by those who have no better argument, it is important to have a figure representing the aim for the foreseeable future, which would not be exceeded unless there was a clear demonstration that more was necessary..
Much more importantly, however, we need to propose an amount which would be enough to provide worthwhile and widespread benefits. The idea of 10% is not just to produce an easily-remembered, conservative and traditional figure, it is also designed as an aimpoint for those who really wish to protect our marine heritage and ensure the sustainability of our marine resources. A network of marine reserves comprising 10% of every type of marine habitat and spread round the country has every chance of achieving these aims, and is a worthy cause for every citizen. 10% is a rallying cry.