Conserving New Zealand's fish stocks at sustainable levels could pay big dividends if world fishing trends continue.

The first information from a worldwide United Nations study suggests many fisheries and the ecosystems which support them face an uncertain future.

The report, due out in full in September, concludes that present fishing fleets are 40 per cent larger than the world's oceans can sustain.


It adds that almost 70 per cent of major marine fish stocks are being over-fished, or fished at their biological limit.

These trends come as Brierley Investments tries to offload its 50 per cent share of New Zealand's biggest fishing company, Sealord.

The Government has barred overseas owners from holding more than 24.9 per cent of the Nelson-based company. The Waitangi Fisheries Commission already owns half of Sealord.

Last year, New Zealand seafood exports earned $1.34 billion, 8 per cent more than the previous year.

While this extra money rolled in, the 322,000 tonnes of seafood exported was actually an 8 per cent drop on the previous year.

A lower average New Zealand exchange rate accounted for a third of the increase.

Fish commodity prices also rose because supply from key fisheries in the Atlantic were under pressure, as demand in America and Europe rose.

The UN prediction is that the ravages of over-fishing and pollution could see many marine species on the brink of extinction within the next decade.

The UN report, Guide to the World Resources 2000-2001: People and Ecosystems, The Fraying Web of Life, is being published by the UN Development Programme, the UN Environment Programme, the World Bank and the World Resources Institute.

More than 175 scientists have contributed to the report, which has taken more than two years to produce.

Despite the grim estimates, Ministry of Fisheries policy manager Mark Edwards believes New Zealand's fish stocks are in relatively good shape.

He cites effective compliance with the vigorously policed quota management system as the reason.

The management of non-target (or bycatch) species is also being addressed by the progressive introduction of measures to reduce any adverse effects of fishing.

"We have a revolutionary system in New Zealand," he says.

Many fisheries worldwide are managed through what are known as input controls, or in some cases catch limits.

Input controls operate by attempting to control the amount of fish that are caught or killed in commercial fisheries.

They include such methods as restricting mesh sizes on nets, the power or size of vessels, or the season over which vessels may operate.

Mr Edwards says those systems have critical shortcomings. They do not necessarily restrain the total amount of fish caught.

New Zealand's quota management system focuses on two major components.

First, the total catch ("removals") for each fish stock is kept to a level that is assessed to be sustainable.

The ministry has implemented a structured research and stock assessment process to provide quantitative estimates of sustainable catch limits for fish stocks.

The second component of the system is that, rather than that being a competitive catch limit, a proportion of that catch limit quota is allocated to each commercial fishery business operating the fishery.

Mr Edwards says this has a number of important benefits.

Firstly, individual fishers know how much they are allowed to catch in any particular year (and there are disincentives for them to catch over that amount).

Secondly, it means operators in the fishery can use equipment at a time that is best for them in terms of processing or marketing returns "rather than competing with looking at all the other guys on the water and thinking about how he's going to race them to catch his share of fish."

Because this allocated quota is also transferable or saleable, Mr Edwards argues that the fisher has a long-term business interest in the state of the fisheries.

"The single most important feature of the quota management system is the positive husbandry incentives introduced by owning your own quota."

Some of the most vigorous debate arises over whether we know enough about New Zealand's fish stocks, their environment and sustainability. The environmental watchdog Forest and Bird Society remains critical.

Fisheries Minister Pete Hodgson has said more money will be spent on research, as it is impossible to properly manage stocks under the present system.

"We can't pretend that we have a good quota management system, because we haven't got a sufficient knowledge base.

"Our knowledge of this environment is very meagre indeed and at current levels of research funding would remain so for the foreseeable future."

Forest and Bird criticised the passing of the Fisheries Amendment Bill affecting the quota management system. They believe the bill "legalises over-fishing."

Society spokesman Barry Weeber said giving the industry greater power to contract fisheries research and maintain critical databases required for setting catch limits would lead to further undermining of fish stocks already under threat.

"Despite the claims about the effectiveness of the quota management system, nearly every orange roughy and oreo fish stock which has been assessed has been reduced below the size which would support long-term sustainable yields," Mr Weeber said.

The total annual orange roughy catch now allowed in New Zealand waters is about 20,000 tonnes, compared with 52,486 tonnes a decade ago.

The ministry's response to the Forest and Bird criticism is that the Fisheries Amendment Bill had not altered the basic purpose and principles of the 1996 act.

It says the bill's provisions are designed to allow greater administrative flexibility for fishers to harvest their catch entitlements within the overriding framework of sustainability.

The revised fisheries management regime provides a number of management mechanisms to impose penalties for over-fishing, it says.

Mr Edwards says the ministry is developing policies and procedures for direct purchase of research by stakeholder groups.

"All stakeholders will be fully consulted on these before approval for direct purchase is considered by the joint Ministers of Fisheries and Environment."

The two research databases most critical for setting catch limits are commercial catch and effort, and fisheries. These databases will continue to be maintained either directly by the ministry or under contract to it.

As the system stands, Mr Edwards says, if assessments suggest a stock has been reduced below target levels, a rebuild programme is implemented through catch reductions and other measures.

The office of the Parliamentary Commissioner for the Environment, for example, recently released a report on managing a sustainable future for the New Zealand marine environment.

It attacked the present management systems and suggested there was a serious lack of knowledge of our marine environment "which poses grave environmental and economic risks to New Zealand."

The New Zealand Seafood Industry Council chairman, David Sharp, told a Maori commercial fisheries conference in Nelson in May that the industry needed to ensure it was not landed with ever-increasing research costs brought about by calls for more information on the marine environment.

While such research was important, there was a danger of overdoing it, he said.

It was also important the research did not automatically become a cost to the industry.