Marine – Purse seining ban long overdue

The decline of available food sources for snapper and other creatures won’t improve if indiscriminate purse seining of important food sources continues in the Hauraki Gulf Marine Park. Earlier this year, Ministry for Primary Industries reports showed that snapper in the Gulf are starving, pointing to ecosystem collapse and a lack of food available as causes.

But snapper aren’t the only ones struggling to find food – seabird species are leaving their gulf feeding grounds to go on long trips south to bring food back for their young.

Small schooling fish species, known as forage fish or bait fish, are important food sources for larger fish such as kingfish, seabirds and mammals including dolphins. Forage fish include anchovy, mackerel, pilchards and kahawai. The variety and numbers of forage fish are declining.

There are many contributing factors to the decline in available food sources. An estimated 4 million kilograms of forage fish are purse seined out of the Hauraki Gulf every year. Purse seining works by setting a large net, sometimes up to two kilometres long, in a circle around the bait school and then drawing the net in slowly to create a ‘purse’. In the Hauraki Gulf Marine Park, the most fish caught, by weight, is blue mackerel – a fish much smaller than snapper. Using a seine net, thousands of mackerel can be caught in one set.

Fisheries New Zealand puts little effort into measuring the effects of taking so many fish. In December 2019, an estimated 1000 kilograms of dead mackerel were ‘accidentally lost’ from a commercial vessel, some of them washing up on the shores of Kawau Island. And, around 90% of blue mackerel is exported, usually as frozen food or bait.

Seafood New Zealand statistics show whole, frozen blue mackerel is being exported for around $1.80 a kilo. At this bargain basement price, we need to rethink our priorities in favour of sustaining the environment including our birds, mammals and other fish species. The Minister for Oceans and Fisheries has the authority to ban any fishing method on the basis of sustainability. Banning purse seine fishing means we can protect the food sources that are so important to sustaining the sealife we treasure, including our snapper, seabirds, dolphins, and whales.