Will Atlantic cod stocks recover?

Source - ICES

The 21st century is a tough time to be a cod.

In the North Sea, the stock is about 53,000t which is a third of the 150,000t that scientists recommend as a bare minimum. On the other side of the Atlantic the situation continues to be critical: Canadian cod stocks collapsed in the early 1990s and despite a complete closure of the fishery, many individual stocks have yet to recover.

To prevent cod stocks in the North Sea, Irish Sea and west of Scotland from going the same way, ICES has been calling for a complete ban on cod fishing in these areas and for the development of recovery plans to rebuild the stocks.

 

The question is, are these stocks ever likely to recover or are recovery plans too little, too late?

Recovery plans were certainly a hot topic at the recent ICES Annual Science Conference in Estonia (September 2003). One of the key figures driving the discussion at a special theme session on recovery plans was Dr John Caddy, a scientist formerly with the UN Food and Agriculture Organisation (FAO).

In a meeting room packed with fellow scientists he reported on his study of fish stock recovery plans from around the world.

He set the scene by describing how the concept of the recovery plan originally began with attempts to save rare terrestrial animals such as endangered wetland birds, but that recovery plans are now very much focused on attempts to rebuild marine fish stocks.

Pelagic stocks
Describing the development of fish stock recovery plans, Caddy related how the first plans were fisheries closures, mainly for herring stocks, and these were generally successful. Both Norwegian spring-spawning herring and North Sea herring recovered from complete collapses in the 1960s and 1970s and now with improved management they continue to support productive fisheries.

This success was partly put down to several years of good recruitment of young fish to the stocks, possibly aided by favourable environmental conditions.

Another reason was that the by-catch of herring in other fisheries was restricted so that when the fisheries targeting herring were closed, the pressure on the stock stopped immediately.

Demersal stocks
Recovery plans for demersal (or bottom-living) fish stocks have not been so successful, the poor recovery of Canadian cod stocks being a prime example.

Caddy suggested that the failure of demersal stock recovery plans was due to a number of causes.

One of the main reasons was that initial measures to reduce fishing pressure were inadequate, taken too late or undermined by the problem of mixed fishery issues.

Several species of demersal fish are generally caught together in mixed fisheries where the fish are sorted on the deck of the fishing boat and it is difficult to selectively avoid catching badly depleted stocks such as cod.

When a ban is advised on all catches of one demersal species – such as ICES advised for North Sea cod in 2002 and again in 2003 – it affects many other demersal fisheries as even though they may often target other species such as Nephrops or haddock they will be unable to avoid catching cod as well.

The complete closure of demersal mixed fisheries to save one species is a bitter pill for stakeholders and politicians to swallow. As a consequence, recovery plans are often not fully implemented.

Failure of management measures
These are not the only reasons for the poor success of demersal stock recovery plans. Other causes, put forward by Caddy, include the failure of management measures to control the amount of fish removed from the sea, as highlighted by the thriving illegal, or “black” landings market in many countries.And the failure of technical measures, such as the introduction of bigger mesh sizes to allow more young fish to escape, which have often been compromised by fishers manipulating their gear in order to reduce or nullify the effects of the regulation.

Another cause is the wild card of environmental variation or ecological changes. Although there is a consensus that overfishing was one of the main causes of the collapse of the Canadian cod stock, it is thought that adverse environmental conditions (e.g. colder waters) also played a part, and continue to slow the recovery of the stock.

Slow recovery
Even with favourable environmental conditions demersal stocks are generally slower-growing, later maturing fish than their pelagic cousins and so they will naturally take longer to recover.

Caddy observed that experience shows that time-scales of a decade or more should be considered the norm for demersal fish. This is certainly proving to be the case with Canadian cod stocks. Initially the stocks were expected to recover in 3-4 years after the fishery was closed, but 11 years later many stocks have still not recovered.

In a separate presentation, Canadian scientist Jake Rice attributed the over-optimism in the scientists’ original predictions to the fact that they were based on the reproductive potential of the stocks when they were in a healthier, more fertile state. In reality, when a stock has reached a historical low, it is less fertile and often outside the range of the scientists’ models and experience, so there is great uncertainty as to how the stock will react.

Importance of older cod
Another issue raised by Caddy, particularly in relation to the recovery of demersal stocks, is the seeming importance for the stock of having a good age structure i.e. plenty of older, larger, more fertile fish as well as the young ones.

Species such as cod, which have the potential to reach an age of 25, frequently suffer poor reproductive success during times of unfavourable environmental conditions (for instance colder waters).

Scientists believe that a good reserve of older, more fertile fish are essential to kick-start recruitment when conditions are better again.

Unfortunately, current fishing practices which naturally tend to fish down the age structure, removing the older fish, mean that the stock loses the big spawners and so recovers more slowly after a period of poor conditions.

Observer schemes
Once recovery plans are in place for badly depleted stocks, Caddy stressed the importance of having credible, independent monitoring schemes in place to see what is going on in the fishery. These should act as a check to reduce the effects of misreporting by fishers and subsequent over or under-estimation of the stock size by scientists.

Following on from this, it was interesting to note in discussions among the scientists that distrust and criticism of the science by stakeholders was remarkably similar in both the Atlantic and Pacific Oceans. Caddy suggested that from the scientific viewpoint it is essential to change human behaviour from a culture of harvest to one of sustainability.

Learning from the Canadian experience
In summing up the lessons learnt from the collapse of Canadian cod stocks, Jake Rice stressed the importance of acting quickly when stocks are in decline. Experience in Canada has shown that in general, those cod stocks that were less depleted recovered more rapidly.

He also highlighted the need to let stocks recover fully before re-opening fisheries. When some of the Canadian stocks showed signs of recovery, restricted fisheries were re-opened and the small increase in stock size was quickly wiped out.

Finally, he emphasized the crucial importance of permanently removing over-capacity in fisheries. In Canada the fishing capacity and demand for fish are still as high now as they were when the fishery was originally closed in 1992. As a result the reintroduction of bans on cod fishing in 2003 was resisted just as strongly by stakeholders as it was 11 years ago; the big difference is that this time there are no expectations that things will get better in the near future.

Future for Atlantic cod
In answer to the question raised in the opening sentences as to whether cod and other depleted stocks will ever recover, the answer is that nobody really knows. But what came out clearly from the world-wide study of recovery plans was that the quicker the action is taken to stop stocks collapsing, the more chance there is of success.

Caddy highlighted the fact that for recovery plans this means a significant, immediate reduction in catches rather than a gradual approach to protect short-term economic interests, which simply prolongs the recovery period.

The most successful recovery plans were those where objectives and control rules were already pre-agreed. Legislation which is intended to remove the option for political weakening of recovery plan measures, e.g., as in the USA with the Magnuson-Stevens Act, is very important and can be an extremely useful management tool.

Discussing the status of the recovery plans for North Sea cod, Caddy stated that;
“Although workable models for a recovery plan were available since 2002, they have not been implemented, suggesting that the problem is operational and not due to a failure of scientific advice”.

He also stated that probably the single factor that is most likely to jeopardize the success of the cod plan will be the continued allowance for political intervention, even when the plan is adopted.

As a final point, in light of the worldwide experience trying to restore depleted fish stocks, Caddy commented that perhaps recovery plans should in future be known as “emergency plans”, as unfortunately there is no guarantee that stocks will ever recover.

By Neil Fletcher

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