Fish farm will 'ruin' harbour

19:23, Nov 07 2012
AQUACULTURE: Oyster farms at Whangaroa, viewed from St Pauls.

It would be disgraceful if a proposed 25-hectare fish farm was approved for Owanga Bay in Whangaroa Harbour - or anywhere else in Whangaroa harbour for that matter, John Greenfield of Kerikeri says.

Mr Greenfield has worked all over the world for 40 years, with large companies and the United Nations in agricultural development, and for 18 years as senior agricultural adviser with the World Bank.

"From my experience I soon learned the importance of access to the sea, it's a no-brainer.

"Countries need unimpeded access to the sea for exports and imports.

"All over the world, rivers run into harbours and as population densities increase, so does the extra erosion from the farms' silt up these harbours."

He says it was disheartening to come back to New Zealand to find our harbours being blocked by activities such as oyster farming.


"Any obstruction in a harbour will create a permanent silt trap, once the farms are abandoned, mangroves start to grow and take over. The government doesn't think about this.

"We are already seeing how oyster farming contributes to flooding in Kaeo."

A fish farm in Whangaroa Harbour - where most yachts seek safe harbour in Owanga Bay - would ruin that area's integrity permanently, denying access to the yachts, he warns.

Mr Greenfield has sent the Northland Regional Council information from a European/US non-government organisation, Food and Water Europe, pointing out the failures and problems with such factory farms.

"These enterprises, once they fail - and fail they will - are like a cancer on the seabed having poisoned the fish life in the immediate vicinity their residues would take years to clean up."

He says factory farming just doesn't work, neither on the land nor in the sea, where it's hazards are hidden under the water.

The biggest problem faced is cleaning up the seabed once the fish farm is abandoned.

Mr Greenfield has obtained figures from the Northland Regional Council that show there is an estimated 25,600 cum (6400 tonnes) of waste oyster shell and 270 cum (297 tonnes) of waste timber in the Waikare Inlet to be recycled from 30ha of oyster farm (213 tonnes/ha of shells and about 10 tonnes of wood/ha).

Work will start in the middle of this month, says Dr Jacquie Reed of Northland Inc, a Northland Regional Council controlled organisation. The three-year clean-up timetable involves bringing shells and waste timber to land for recycling.

The $3.8m cost of the joint venture involves central and local government and the industry: The oyster industry is contributing $1m, the Ministry for the Environment $2.1m and the Ministry for Primary Industries $300,000.

Bay Chronicle