The precautionary approach
Article published in Fishing News, 30 April 1999
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
Cefas, explains the precautionary approach.
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 worldwide 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 worldwide and this is reflected
in new international agreements aimed at promoting the sustainable
management and conservation of fisheries:
International use of the precautionary
approach
- UN Agreement on Straddling and High Migration Fish Stocks
- FAO Code of Conduct for Responsible Fisheries
- Strategies developed at the 1997 intermediate ministerial
meeting of the North Sea Conference on the Integration of Fisheries
and Environmental Issues
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.
| North Sea
cod |
|
| Spawning stock biomass
(B) in 1998: |
136,000 tonnes |
| Danger level (red light)
(Blim): |
70,000 tonnes |
| Precautionary level
(amber light) (Bpa): |
150,000 tonnes |
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.
For readers with access to the Internet, 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 website.