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Seafood and sustainability

Reviewed by our expert panel
Seafood and sustainability

Senior nutritionist Rose Carr investigates the question: could our days of eating seafood be coming to an end?

Nutritionists like to recommend we eat at least two fish meals every week: fish is a low-fat source of protein and it’s the best source of long-chain omega-3s which are believed to have many health benefits. On the other hand, we are told overfishing is depleting the world’s fish stocks and perhaps our days of regularly enjoying fish are numbered. This may be hard to accept when we can still purchase such a wide selection of fresh fish, albeit for a price.

Environmental groups, however, are not saying, ‘Don’t eat fish’, but they are urging us to be more selective about the fish we buy, claiming not all fish on offer is sustainably caught. The fishing industry disagrees. They point to their environmental policies and our quota management system (QMS), administered by the Ministry of Fisheries. So how do we as consumers balance our eating pleasure and health with the effects on both our environment and the economy?

It is widely accepted that the world’s fish stocks are under significant threat. In 2008, the Food and Agriculture Organization of the United Nations (FAO) reported that at least 28 per cent of the world’s fish stocks were over-exploited or depleted. A further 52 per cent were fully exploited, which means the stocks are fished to a maximal level and they are replacing themselves.

The FAO highlights a worldwide overcapacity of fishing dating from the late 1980s. Essentially this overcapacity and overfishing has occurred because of open access to fisheries: no-one was controlling them. Fisheries management has now been introduced in most countries, in varying forms, with varying success.

Worldwide, it is suggested that a 20-50 per cent reduction in current fishing is needed to achieve sustainability, yet total demand for fish is increasing.

Quota management systems found in New Zealand, Australia and Iceland, and becoming more common in North America and the US, have been touted as the way forward in sustainable fisheries. A fishery is defined as one fish species found in a specific geographical location. The economics are such that there is greater incentive for those with catch quotas to protect the fisheries long-term. Under these systems each ‘shareholder’ is guaranteed a fixed portion of a fishery’s total allowable commercial catch, which is set each year based on knowledge of the state of the fishery.

The Alaska halibut fishery is an example of a fishery which recovered through a quota management system. The fishery had declined so much that by the early 1990s, the annual (open access) harvest season was just 24 hours long. By-products of this were over-capitalisation, falling ex-vessel prices, dangerous fishing conditions, and environmental damage. A quota management system was put in place in 1995 despite considerable opposition from people who fish. The Alaska halibut season now lasts 245 days each year and there have been improvements in safety, economic security as well as environmental protection.

Fishing is big business in New Zealand. In 2009, we exported 287,000 tonnes of seafood worth $1.4 billion to our economy. We export around 90 per cent (by value) of all New Zealand seafood. (Interestingly, we also import over $100 million worth of seafood products.) Based on market prices, catch quota and annual catch entitlements, our fish stocks were valued as an asset worth more than $4 billion. Employment in the wider seafood industry is estimated to be the equivalent of 26,620 full-time jobs. Sustainability of our fisheries resource is in everyone’s interests, including those who eat seafood, those relying on it for their livelihoods, and all of us as residents and taxpayers benefiting from the economic activity. So how is that being managed?

There are 130 fish species commercially fished in New Zealand and there are now 97 species managed under the QMS which was introduced in 1986.

Under this system the species are divided into 629 separate fish stocks found in different areas within the waters of the 200-nautical-mile exclusive economic zone (EEZ) surrounding New Zealand.

Quota management systems work by allowing fishing to the point where it will maximise the long-term fishing yield without compromising the sustainability of the fish stock (known as Maximum Sustainable Yield). Each year, based on the calculations by scientists at the Ministry of Fisheries, a total allowable commercial catch is set for each fish stock. However, while the Ministry of Fisheries takes into account the population dynamics of the stock and any environmental factors that influence the stock, (where known), it’s apparent that this is far from an exact science. And this is where the sustainability debate in New Zealand hinges. Assessing fish stocks is both difficult and expensive. Statistical modelling is used: theoretical stock levels are estimated and a range of likely stock levels using different assumptions is also estimated.

The Ministry of Fisheries produces a stock status table showing the probability of fish stocks being ‘near or above target levels’ and in 2009, they added three more indicators to this table: ‘overfishing?’, ‘collapsed?’ and ‘depleted?’.

When a fishery is assessed to have been subject to overfishing this means the catch has exceeded the maximum amount (the maximum sustainable yield) set by the Ministry of Fisheries. When a fishery is assessed as being depleted the Ministry of Fisheries must develop a formal plan to rebuild the stock. When a fishery is assessed as having collapsed, closure of the fishery must be evaluated.

While the main focus of the QMS is the sustainability of fish stocks, the effect fishing has on other species and on the environment is also taken into account by the Ministry of Fisheries. The Department of Conservation and the Ministry for the Environment also take an interest in the environmental impact of fishing.

The New Zealand seafood industry has adopted a ‘fish to fish another day’ approach, investing up to $20 million each year in research on both sustainable fishing and how to minimise their impact on the environment.

Bottom trawling (used for orange roughy and some of the hoki catch) and dredging (used for scallops and oysters) can damage the seabed affecting marine habitats and ecosystems.

The Ministry of Fisheries tell us that repeated bottom trawling (and in some places dredging) since the 1960s and 70s has probably reduced the diversity of life on the sea floor and the productivity of marine ecosystems in most inshore fishing grounds around the country. Some inshore areas have been closed to bottom trawling and dredging, with more closures likely. It is a similar story in offshore fishing grounds, which make up around 10 per cent of our EEZ, with a number of areas now closed to bottom trawling and dredging.

Bottom trawling, middle-depth trawling, longlining and set netting all involve the risk of catching what is known in the industry as bycatch. Bycatch can be other fish species, seabirds and marine mammals including New Zealand sea lions, fur seals, whales, the endangered Maui’s and Hector’s dolphins and other dolphins. Bycatch is required to be reported to the Ministry of Fisheries. New Zealand fur seals are the most frequently killed marine mammal. In the 2007-8 hoki fishing season, an estimated 714 fur seals were caught as bycatch. It is believed around 400-600 seabirds are caught annually in the hoki fishery, around half of which are albatrosses.

So what does this mean when we are in the fish shop or at a restaurant? How do we know which fish to choose?

We have a couple of options. One is to rely on the Ministry of Fisheries and its scientists to look after our fisheries, set appropriate catch quotas and to continue working with the fishing industry to reduce harm to the environment and other marine and bird species. This means we can, in good conscience, buy and eat any seafood that’s available over the counter: under the QMS, if we can buy it, then it must come from a sustainably-managed fishery.

However, there are several reasons we may be uncomfortable with this option. Some would argue that the scientists don’t have enough information to give us reliable data on fish stocks. Also, we are largely relying on reporting from the fishing industry to understand the wider impacts of their activities. It is difficult to know where the balance of power lies between the scientists, policy-makers and industry, when the fishing industry is economically so important to us.

Should we wish to take a more precautionary stance and consider the environmental impacts of fishing, the Best Fish Guide produced annually by Forest and Bird is a good place to start. Like the Ministry of Fisheries, their assessment criteria and methodologies appear to be sound, but again they are limited by the information available.

A key difference is that Forest and Bird take a far more precautionary approach in their assessments of fish stocks. The Best Fish Guide also places greater emphasis on the amount of bycatch and the damage done to the marine environment (see ‘Good fish choices’ below).

On the Ministry of Fisheries website, fish stocks listed as likely to be overfished, depleted or collapsed include:

  • bigeye tuna
  • black cardinal fish
  • bluenose
  • orange roughy (some fisheries have a less than 40 per cent probability of being near or above target levels. Some orange roughy fisheries are closed.)
  • scallop (from the Tasman Bay stock)
  • southern bluefin tuna.

The full table is available at http://tinyurl.com/25xky43/

Your options for choosing which fish to buy

Option 1: Trust the QMS

New Zealand’s QMS is held up around the world as an example of good fisheries management. A recent study evaluating the management of 53 marine ecosystems in the world ranked New Zealand’s QMS as number one. So, if we can buy the fish, it’s okay to eat it.

Option 2: Place greater emphasis on the environment

If you are concerned that the amount of bycatch and/or the environmental impacts are too high, use Forest and Bird’s Best Fish Guide to help you choose. The authors of the above study also state that while we incorporate best practice in the management of our marine resources, there is still room for improvement.

Better fish choices on Forest and Bird’s list include kahawai, John dory, skipjack tuna, trevally and red gurnard.

Poor choices include snapper, southern bluefin tuna, orange roughy, deepwater dory, oreos and arrow squid. See http://tinyurl.com/n2o8qw/

First published: Jan 2011

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