New Zealand will triple marine protection in the Hauraki Gulf, restricting fishing in almost a fifth of the 4,000 square kilometer (2,500 square mile) area off the coast of largest city Auckland to curb pollution and safeguard ecosystems.

The government will introduce 19 new marine protection areas, increasing coverage to 18% of the Gulf from 6% currently, Prime Minister Chris Hipkins said Wednesday in Wellington. It will also ban the practice of bottom trawling and Danish seining from large parts of the area.

The Hauraki Gulf, which lies off Auckland’s east coast, is used for recreational and commercial fishing as well as by tourism operators and sailors. Hipkins said the economic value of the Gulf has been assessed at NZ$100 billion ($60 billion).

“The Gulf, however, is at risk and its ecosystems are under immense pressures, causing concerning declines in marine life and sea bird populations,” he said. “Those who live and work in the Gulf can see it’s changing. There’s more pollution and fewer birds.”

The government will create 12 high-protection areas to protect and restore marine ecosystems, while allowing for customary practices of indigenous Maori. It will extend two existing marine reserves, and create five new seafloor protection areas to preserve sensitive habitats by prohibiting bottom-contact fishing methods.