Scientist calls for urgent marine protection


Tensions were high at a meeting last week to discuss 12 new marine reserves proposed by Waiheke Local Board.  While marine biologist Roger Grace says the seas around Waiheke are shockingly degraded and urgent action is needed to protect marine life, Keep Our Beaches and some fishing folk are strongly opposed to reserves on the northern coast of Waiheke.
Marine biologist Roger Grace says marine reserves are urgently needed to protect Waiheke’s northern coast from severe degradation.
At a meeting on Waiheke last week, Dr Grace gave a presentation explaining his marine reserve proposals which would see large areas of Waiheke’s northern coast protected in ‘no take’ reserves.
Some of the areas included in his plans for marine reserves are Enclosure Bay, Nani Island off Palm Beach, and Thomspon’s Point near Onetangi Beach, where kina have destroyed kelp forests and created barren underwater deserts.
“They are some of the worst kina barrens I have ever seen.
“If something is not done soon, you are going to lose all the kelp on the north coast of Waiheke. It’s really quite serious,” said Dr Grace, who surveyed Waiheke’s northern coast three years ago.
Kina are proliferating because about 80% of the original numbers of snapper have been caught by commercial and recreational fishers, and crayfish have also been severely reduced in numbers on the east coast of the North Island.
This leaves one of their “favourite foods”, kina, to become unnaturally abundant.
“Seriously degraded reef systems are extensive throughout New Zealand. This has been brought about by not leaving enough snapper and crayfish to keep kina numbers under control.
“Where there was kelp forest, now there is bare rock with hundreds of sea urchins chewing the surface.
“When you lose all that kelp, you lose hundreds of species. Kelp is very important to maintain a high level of biodiversity.”
Tangled kelp also helps keep sediment washed off the land from settling on the sea floor and smothering sea life.
“It’s a much more serious situation having kina barrens on the Waiheke coast because of the silt.”
Dr Grace says the recreational fishing park that has been proposed by the government will do nothing to improve the “sad state” of the Hauraki Gulf.
“They are not going to do anything for biodiversity protection with a recreational fishing park in the gulf.”
In areas where commercial fishing has been banned but recreational fishing continues, such as Mimiwhangata, snapper and crayfish numbers are still too low to stop kina destroying kelp forests.
However, Dr Grace has worked in marine reserves at Tawharanui and Goat Island, where fish stocks have been restored and kelp forest has returned.
Snapper can live to as old as 60 years, and older fish produce more eggs and breed more often, while also being large enough to crunch kina.
However, snapper seldom have a chance to mature outside of marine reserves.
“In a heavily fished population, you lose almost all your big fish, which serve a different ecological function than small fish.
“In the Hauraki Gulf, most snapper disappear at six to seven years old, there is only the odd big one.”
Dr Grace noted that about 30% of the land in New Zealand is protected in reserves, but only 10% of New Zealand’s territorial waters are set aside in marine reserves and less than 1% of the coastal waters around the country are protected in reserves.
“Marine protection is a long way behind and it needs to be addressed.
“Our fisheries have been seriously depleted and are just a shadow of what they used to be.”
While there are six marine reserves in the Hauraki Gulf, only 0.3% of the gulf is set aside in no take reserves.
“That’s pathetic. It’s enough to show us what marine reserves can look like but it’s not enough to make a difference to biodiversity or fish abundance outside the reserves.
“I believe 10% is an achievable goal.”
Marine reserves create an abundance of fish that spreads to nearby areas where fishing is twice as successful, he said.
At Tawharanui marine reserve, which was established in 1981, 1000 crayfish per hectare have been recorded compared to levels of almost zero outside the reserve.
“When you protect an area from fishing, crayfish respond well and become really abundant. It could happen at Waiheke,” said Dr Grace, who recalled crayfish being plentiful around Waiheke in the 1960s.
However, marine reserves need to be about 40 square kilometres in size to restore natural populations of fish and other marine life.
Goat Island marine reserve has suffered from falling numbers of snapper and crayfish, due to heavy fishing on the boundaries of the reserve.
While thousands of hours of volunteer labour are needed to create sanctuaries for birds and other wildlife on the land, marine life can be restored by simply “stopping fishing”.
“National parks and marine reserves become more and more valuable the longer they stay in place and the biodiversity becomes much more natural.
“We should be looking at whole systems or networks of marine reserves,” he said.
Auckland University of Technology lecturer Dan Breen, who lives on Waiheke, described processes of consultation with different groups that were undertaken in Australia, where he worked on establishing networks of marine reserves.
He noted that recreational fishing areas could act as useful buffers around marine reserves.
However, he made a submission to the government on its planned Marine Protected Areas Act, saying that the fishing park had been proposed “without any consultation”.
Too many different agencies would be involved in managing the fishing park, which would be better managed by a single authority focused on improving biodiversity, said Dr Breen. • Rose Davis

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