Cod stocks in trouble

The recent ICES advice (October 2002) relating to cod and associated species is the result of the cumulative failure to control fishing pressure on a range of stocks over the last decade.

As long ago as 1992 ICES advice was, 'Recovery of the cod stock would require, at minimum, a marked and sustained reduction of effort or even a closure of the fishery'.

The advice was repeated in 1993. In 1996 ICES noted that 'recent analyses …suggest that the stock may collapse under fishing mortality rates above 0.75. Present fishing mortality is above this level.'

ICES also stated that, 'As it is unlikely that a lower fishing mortality can be achieved by the application of technical measures and or TACs/quotas alone, ACFM believes that the required decrease can only be achieved by a reduction in effort in the directed fisheries for cod and the mixed roundfish fisheries which take a large cod component'.

It is quite clear that ICES believed that substantial action was required many years ago and warned that traditional management tools were not working.

"ICES advice relating to cod and associated species is the result of the cumulative failure to control fishing pressure on a range of stocks over the last decade"

More recent advice in 2000 and 2001 was 'that fishing mortality on cod should be reduced to the lowest possible level' and re-iterated the failure of TACs to bring about the necessary reduction. This advice was only one step short of a closure.

In 2002 the seriousness of the cod problem prompted the North Sea Commission Fishery Partnership to conduct a thorough review of the ICES cod assessment.

It was carried out by three independent North American scientists chosen, not by ICES, but by the Partnership. Both the Scottish Fishermen's Federation and the National Federation of Fishermens Organisations participated actively in the review. The industry knew in August exactly what was in the assessment and agreed that it provided a fair interpretation of the state of the stock (Fishing News 6 September 2002).

Much has been made in the press about the industry survey contradicting the scientific assessment. Yet the industry survey was also reviewed in August by the Partnership and found to be entirely consistent with the ICES assessment. The survey notes the absence of cod in the southern North Sea and its 'spotty' distribution.

Sadly this does not indicate fish have moved north but that large areas are now critically depleted. This is a classic symptom of a stock close to collapse and happened with the Canadian cod and the North Sea herring before their demise.

But why, if both the industry survey and the ICES assessment indicate more cod in 2002 compared to 2001 does ICES recommend a closure?

The reasons are twofold.

Graph shows the long-term decline in one year old cod.

Firstly, the current death rate of cod, due to all factors, exceeds the rate at which recruits are being produced. It does not matter whether the deaths are due to fishing, seals, temperature change or disease, the stock has been ground down so much that it simply cannot produce enough juveniles to compensate and is in long term decline. You can see this in the figure which shows the numbers of one year old cod produced each year since 1963.

The numbers vary a lot but are declining, with the most recent years the poorest on record. The variation explains why some years are better than others, but whichever way you look at it the trend is downward.

Secondly, the current assessment has revised the estimate of spawning biomass in 2001 from 50,000t down to only 30,000t. This change in the assessment has been seen before and shows that ICES has tended to under-estimate the rate of decline of the stock.

The estimated increase in 2002 to 38,000t is still well below the previously calculated lowest value and there are fears that it too, may be over-optimistic.

The apparent improvement in 2002 is temporary and is likely to reverse in the next few years. That could happen rapidly and irreversibly as happened in Canada.

Fishing is virtually the only factor we can control, so if we want a sustainable fishery for cod in the future, it is fishing pressure that we have to reduce. And because the reduction has been left so late, it has to be very big and very soon. Recent decommissioning is a step in the right direction, but unfortunately it is simply not enough to halt the decline.

For Scotland, and some English boats there is an added problem. Since 1999 there have been no good year classes of haddock in the North Sea.

That means the stock will decline rapidly after 2003 and unless a good year class appears soon, haddock could also collapse. The signs are that 2004 could be a crunch year for roundfish boats. We need to plan to face that problem now, it is not just cod that are in jeopardy.

Scientists have wrestled with the problem of this very difficult advice knowing that it will have huge implications. It was not given lightly and it remains only scientific advice. The management challenges in dealing with it are enormous but they need to be faced if we are to have sustainable fisheries in the future.

Author
Dr Robin Cook, Director of Fisheries Research Services, Aberdeen

This article was originally published in Fishing News 6
December 2002.

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