Publication Abstract

The Precautionary Approach

The industry was angered by quota cuts this year resulting from the sudden introduction of the ‘precautionary principle’ into the process of setting the TACs. Dr Joe Horwood, of MAFF’s CEFAS Laboratory in Lowestoft explains the precautionary approach.

(This article was first published in Fishing News, 30 April 1999)

Last November the Advisory Committee on Fishery Management (ACFM) of the International Council for the Exploration of the Sea (ICES) gave advice for 1999 TACs. The advice was given in terms of a ‘precautionary approach’ for fisheries management. Has the basis for the advice changed?

In this article I will explain why ICES has adopted the principle of a precautionary approach and how ICES has interpreted the precautionary approach.

Why a precautionary approach?

Fish stocks world-wide are under pressure. Many stocks suffer from fish being caught at too early an age – this is called ‘growth-overfishing’. Sometimes stocks can be reduced to too small a size to replenish themselves, which is known as ‘recruitment-overfishing’. Other stocks have collapsed and others are threatened by environmental degradation.

There has been mounting international concern about overfishing and the poor state of fish stocks world-wide and this is reflected in new international agreements aimed at promoting the sustainable management and conservation of fisheries:

What all these agreements have in common is that they require national and international bodies to take a precautionary approach to the management of fisheries.

Each year ICES is asked by fisheries management bodies, such as the European Commission and the North East Atlantic Fisheries Commission (NEAFC), to provide advice on the status of fish stocks and on future catch levels. Increasingly that advice is sought and given in a form which provides for a precautionary approach to fisheries management.

What is the precautionary approach?

There is not one single precautionary approach, but in the various agreements there are common themes. Fisheries can collapse due to overfishing, therefore fishing needs to be kept at levels which ensure the sustainability and productivity of stocks. This constraint is very familiar in fisheries management.

But the precautionary approach goes further. It recognises what fishermen have always known: that advising on maximum levels of fishing and the minimum safe size of stocks required to ensure sustainability, is difficult to do with absolute accuracy.

The precautionary approach requires fisheries managers to take account of the uncertainty in managing stocks. This is done by setting reference points – in effect trigger levels at which action is to be taken.

The precautionary approach reference points

In giving advice last year ICES identified two key types of reference points: ‘limit’ and ‘precautionary’ reference points. The basic idea is that we should be managing fisheries to avoid breaching the precautionary reference points. We can then be reasonably confident that limit reference points – at which there is a serious risk of stock collapse – are never in practice reached. The reference points act as an amber warning light (the precautionary point) and as a red danger light (the limit point).

So how do these reference points work?

If we take a stock – say North Sea cod – there are two important questions for fisheries management: what is the level of the spawning stock?; and what is the level of fishing mortality taking place?

Both of these have to be thought about when decisions are made about management of the stock.

Reference points for spawning stock

For the spawning stock the scientists make an estimate of spawing stock biomass. It is the weight of all the mature fish in the sea of that particular stock. It varies from year to year because of the varying numbers of recruits into the stock and the impact of fishing and other factors affecting mortality. Recruits are the young fish which survive from each year’s spawning to enter the fishery.

For North Sea cod the most recent estimate of spawning stock biomass was 136,000 tonnes. In order to apply the precautionary approach the scientists have established two reference points for the spawning stock biomass.

For North Sea cod the red danger signal is if the biomass falls below 70,000 tonnes. This is the lowest level that the stock has ever been known to fall to and the scientists have proposed it as the limit below which the stock must never be allowed to decline. For North Sea cod the biomass limit (Blim) is 70,000 tonnes.

Using the precautionary approach the intention is that the stock should – if at all possible – be kept well above the danger level (Blim) and so a precautionary level (Bpa) is set at a higher level which gives reasonable certainty that in spite of year to year fluctuations the stock will stay above Blim.

The precautionary level (Bpa) has been proposed at 150,000 tonnes for North Sea cod. This is the previous Minimum Biologically Acceptable Level (MBAL), below which there is an increased risk of low numbers of ‘recruits’. Recruit numbers fluctuate naturally from year to year but can collapse if the parent stock gets too low.

Reference points for fishing mortality

Fishing mortality is a measure of the proportion of fish taken from a stock each year by fishing activity. High fishing mortality can threaten the future of a stock and to ensure sustainability the level of fishing mortality needs to be taken into account in setting quotas. As with the biomass, two reference points are set for fishing mortality (F).

These are:

• Flim – the level of fishing mortality at which there is an unacceptably high risk that stocks will collapse;
• Fpa – a lower level of fishing mortality which offers a high probability that (Flim) will never be reached.

How are those reference points to be used?

The basis for ICES advice is that stocks should be managed to keep the mature stock above Bpa with fishing mortality rates below Fpa. This offers an adequate safety margin to ensure that stock size and fishing mortality never reach danger levels (i.e. Blim or Flim).

In giving advice this year ICES presented assessments of the main commercial fish stocks. ICES set firm limit reference levels for the stocks, but it only ‘proposed’ the precautionary reference levels, in recognition that managers have an important role in identifying the levels of risk acceptable in managing stocks.

ICES advised that catch options which took stocks below their precautionary reference points for biomass (Bpa) or above their precautionary fishing mortality rates (Fpa) would not be consistent with a precautionary approach to fishery management.

Advice for the management of North Sea cod shows the application of the new approach. Figure 1 illustrates the relationship between the recruitment of one-year-old cod (in millions) and the weight of the mature stock of cod (in thousands of tonnes) which spawned those recruits. The spread of points shows the great natural variability of cod recruitments. It also shows the reduced recruitments associated with lower stock sizes.

Figure 1. Recruitment, as numbers in millions of cod age one, against the weight of the mature cod stock, in thousands of tonnes. Note the high variability of recruitment and the lower recruitments at low stock sizes. The lines indicate the fishery reference points Blim and Bpa, and the ReD – danger zone; AMBER – precautionary zone: GREEN – safe zone.

For this stock ICES determined Blim and Bpa at the levels noted in the box above. For a decade ICES has been advising that the North Sea cod should be managed to ensure a stock size above 150,000 tonnes and so the level advised for Bpa has not changed this advice.

ICES also recommended that the danger level for fishing mortality (Flim) should correspond to a maximum removal of 53% of the stock each year. Taking account of the uncertainties ICES proposed that the precautionary level for fishing mortality (Fpa) be set to correspond to a removal of 44% a year.

Such a precautionary fishing mortality would provide a reasonable guarantee that the actual fishing mortality was indeed below Flim and that there was only a small chance of the spawning stocks falling below Bpa in the medium or long-term. In 1998, about 45% of the stock was being fished each year – a little in excess of the precautionary rate.

On this basis ICES advised that the TAC needed to be below 134,500 tonnes to be consistent with a precautionary approach to fisheries management and in fact recommended a catch of 125,100 tonnes to quickly move the stock above 150,000 tonnes.

EU fisheries ministers finally agreed on a TAC of 132,400 tonnes for 1999 down 7600 tonnes from the 1998 level of 140,000 tonnes. The decision should ensure the stock is at or very near the 150,000 tonne level at the end of this year. The reduction in the TAC is primarily due to the lower recent recruitments rather than the precautionary advice as such.

Moving the goal posts?

In recent years ICES advice has been based on a comparison of the state of the stocks with their established Minimum Biologically Acceptable Levels (MBALs). How do the new reference levels (Blim, Bpa, Flim, Fpa) compare with the MBALs?

In practice the proposed Bpa is the same as the MBAL for many stocks. In the case of North Sea cod it is exactly the same. Thus the warning level – the amber light – has not really changed. But it has now been taken more seriously partly because the presentation is clearer and partly because of greater concern about the longer term future for fishing.

Past ICES advice also covered levels of fishing mortality when problems were seen to exist. For example, for some years ICES has expressed concern about the level of fishing mortality on North Sea roundfish, especially on cod. It also advised on the levels of mortality to avoid growth-overfishing. The introduction of the new fishing mortality reference points (Flim, Fpa) means that these statistics are now presented for most stock as a matter of routine so that fisheries managers can take them into account.

The new form of advice should mean that the basis of advice is clearer and more consistent across stocks. The fishery reference points have certainly been moved more into the spotlight so that fishermen, managers, consumers and environmentalists can better judge whether stocks are being suitably managed.

So far as the 1999 TACs and quotas are concerned I consider that the precautionary advice gave ministers a clearer view of the decisions they had to make. Where cuts were made, it was the state of the stock rather than the form of advice which was the key factor.

Long term management strategies

The implementation of a precautionary approach for fisheries management is likely to increase the move towards developing longer term management strategies for more stocks. Such longer term strategies have already been introduced for North Sea plaice, North Sea herring and mackerel: these are all stocks jointly managed by the EU and Norway.

Both the EU and Norway see that there is an advantage in taking this further and it has now been agreed with Norway that we should develop long-term management strategies for North Sea cod, haddock, whiting and saithe, and that we should review the present strategies for mackerel and plaice in the light of the new ICES advice.

In conclusion

The use of some technical jargon has been unavoidable in providing this explanation of how ICES is seeking to apply the precautionary approach in its advice. I hope I have, nevertheless, succeeded in improving understanding of where the precautionary approach comes from and what it means in practice.

It offers a basis for sustainable management of fisheries, to the long-term benefit of fish stocks and the fishermen who rely on them for their livelihoods. It should considerably reduce the risk of stock collapses – such as the Grand Banks cod and North Sea herring – occurring in future.

For these reasons I believe that fishermen have much to gain from the precautionary approach. However, I do understand that the speed of its development especially over the autumn of 1998, has been rapid and we need to explain to fishermen what it all means. As fisheries scientists from CEFAS meet with fishermen around the coasts in 1999, as part of the pre-ICES working group meetings, we will be able to explain the reference points for each stock, and some of the wider implications of the precautionary approach not touched upon above. Meanwhile, I hope this article provides a first explanation.

Detailed information is available on the status of the stocks, the ICES advice and the new precautionary approach reference points. It can be found under ‘ACFM’ on the ICES Web Site.