Managing our Catch

It is almost 22 years since New Zealand brought in a quota system for managing its commercial fisheries.

Almost all major commercial species are now included in this system. They are managed in a way that lets us catch the greatest weight of fish, year after year, in a sustainable way. This is called managing for Maximum Sustainable Yield (MSY). This means finding the delicate balance between taking what we’d like now, and leaving enough in the water to grow and breed for the future.

However, to get this balance right we need a lot of information. Knowing how quickly different species grow and reproduce, and how long they live, helps us to work out sustainable catch levels. These levels are then adjusted as more information on catches and abundance is gathered.

Commercial fishers must report their catches to the Ministry of Fisheries. This information can be used to work out trends in catch rates, and in some cases gives an idea of abundance.

Knowing the catch rates and the size and age of fish caught is often enough to tell us how sustainable a particular catch level is. So, in most important fisheries, we also gather information about length and age of fish caught. This mainly comes from Ministry of Fisheries observers on board fishing vessels and sampling by researchers in fish processing sheds. Some information is gathered by the industry’s own research programmes.

Where even more detailed data is needed, this can be collected through surveys by research vessels or tagging studies. However, these methods tend to be used only on our more valuable fisheries.

Where we have little information, it is hard to gauge how close a fish stock is to its target level. In these cases, the Government must act cautiously, and set the catch at what it thinks is a safe level.

Recreational fishers sometimes want different things from a fishery than commercial fishers. Often they want to be able to catch larger fish more easily. This may mean reducing catches to below the MSY level, so that more fish can grow larger. However, lowering catch limits to be able to catch bigger fish might not be what commercial fishers want. Deciding on the right management approach can be challenging!

When catch levels need adjusting, the government seeks advice from Ministry of Fisheries’ scientists and managers, as well as from commercial, recreational and customary fishers, environmental interests, and the wider public.

New Zealand fisheries management is not perfect. In the past some of our fish stocks have been over-fished. With only four million people, and the fourth largest EEZ in the world, we simply can’t afford the science needed to manage all fisheries exactly at their Maximum Sustainable Yield.

The government must be cautious whenever it sets catch limits so that New Zealand’s fisheries will continue to provide food and jobs for future generations.