Cockle beds still in perilous state

DEATH BEDS: Researcher Dyllan Cochrane, left, and Dr Roger Grace check the Whangateau cockle beds.
DEATH BEDS: Researcher Dyllan Cochrane, left, and Dr Roger Grace check the Whangateau cockle beds.

Whangateau Harbour cockle beds look to be in the grip of another die-off.

But results from shellfish samples sent to the Ministry for Primary Industries could take several months, Whangateau HarbourCare group marine scientist Dr Roger Grace says.

Time isn't an issue as the beds are already closed to harvesting.

But after the first die-off in early 2009 residents were outraged when the ministry wouldn't close the beds till after the peak harvesting season the following summer.

There were real fears the beds could be destroyed by big numbers of harvesters, Grace says.

A voluntary ban backed by hapu Ngati Manuhiri the following summer was seen as a failure with reports of more gatherers than usual, apparently trying to get in before the official ban was enforced.

MPI's three-year ban was renewed last year.

The time the ministry takes to make such decisions is one of the beach community's biggest gripes regarding coastal management.

Another is lack of regional decision-making, putting in piecemeal bans, which increases pressure on beds in other areas, Barry Luckman of Army Bay says.

Luckman is among residents alarmed at the high numbers of gatherers at Okoromai Bay in Shakespear Regional Park this summer.

He sees closures of southern beaches as the cause.

Many critics want a change to coastal management around Auckland.

Any shellfish bans are ultimately the ministry's call and are generally based on periodic survey results.

Decades-long monitoring in Whangateau Harbour had made it clear the die-off had devastated the beds, Grace says. But even in their seriously depleted state, remaining shellfish numbers wouldn't normally have triggered a closure elsewhere, he says.

He fears the beds will be hammered once the ban is raised, especially if Okoromai is also closed.

Monitoring is the key to management of shellfish beds with the ministry checking 12 beaches across Northland, Auckland, Waikato and the Bay of Plenty, though not the same ones each year.

Okoromai Bay and Whangateau Harbour are two of four Hauraki Gulf sites the ministry regularly checks.

Community groups through the Auckland Council have also started monitoring shellfish in 20 sites around the Auckland coastline, based on the monitoring at Whangateau started by Grace.

These results are taken into account by MPI although with most sites' records running for less than 10 years, data is considered too young to give accurate long-term population trends.

Monitoring in the south has seen Eastern Beach permanently closed for about 15 years.

Cockle Bay at Howick has a season ban each year from October to April. Further south at Maraetai, Umupuia has had a rolling ban for more than six years, the latest one due to expire this year and imposed after iwi placed a rahui or voluntary ban on the beach. But monitoring in the north is scant.

Although it is still monitored, Cheltenham Beach on the North Shore has been permanently closed since the late 1990s after the shellfish population crashed.

Further north there are no beaches monitored until Okoromai Bay, which is surveyed almost every year. This shows cockle numbers, while fluctuating naturally, have remained relatively stable with numbers of harvestable adults high compared with most other beaches.

The results of a survey by ministry contractors last month will also take months to be released.

Results from last year's survey have yet to be made public. Beds at Ngaio Bay in the Mahurangi Harbour are covered by students from Mahurangi College and community groups look at Sandspit and Whangateau harbours.

While MPI says it checks Mangawhai most years, further north things get patchy.

In the past eight years Ruakaka has been looked at twice and banks in Whangarei Harbour and around Whangarei Heads up to four times.

Beds at Ngunguru and Pataua have only been looked at once in that time.

Cockle numbers in the beds are increasing at virtually all the 12 Northland, Auckland and Bay of Plenty sites according to a 2012 ministry report. But the numbers of big harvestable shellfish continue to decline. The big shellfish are the breeding stock, releasing spat into surrounding waters.

Aside from closed beaches, harvestable shellfish are at or close to the lowest numbers recorded, the report says.

Big shellfish at growing urban areas in Mangawhai, Ruakaka and Ngunguru have plummeted.

It seems remaining adults are releasing enough spat into the water for the beds to stay viable.

But concerned residents say current practices only manage specific recreational species, leaving most other marine life around the coast unprotected.

Rodney Times