PART II: SEA
FISHERIES SCIENCE
AND RESEARCH
2.1 Fish and shellfish are wild resources
which, if managed properly, can provide sustainable benefits to
mankind. If the fisheries and their environment are managed badly
then stocks and fisheries can collapse. Management of such wild
resources requires a high level of monitoring and scientific support.
Because fish are hidden in the sea, extend over considerable geographical
regions and depths, and are part of a complex ecosystem, there
are considerable scientific and logistical challenges.
2.2 In EU waters UK fishermen catch fish
and shellfish against 60 quotas of over 20 species. They also
catch many fish which are not managed by quotas. In the North
Sea alone they may expect to encounter over 100 species of fish.
2.3 Sea fish undergo extensive geographical
excursions, annually and throughout their development from eggs
to adults, and are caught by fishermen from different nations.
Consequently the assessment of populations, often called stocks,
must be on an international basis.
2.4 The assessment of most stocks of interest
to the UK is undertaken through the International Council for
the Exploration of the Sea. ICES is an inter-governmental organisation,
established in 1902, whose role is to promote research into living
marine resources and to provide advice on the sea and its resources.
Its geographical remit is for the North Atlantic and adjacent
seas.
2.5 ICES' Advisory Committee on Fishery
Management (ACFM) uses assessments, provided by international
working groups, to provide advice on the status of fish stocks,
and on the consequences for fisheries and stocks of various catch-options.
ICES' Advisory Committee on the Marine Environment (ACME) provides
advice on the state of the marine environment. The UK is represented
on both Committees, and on the governing bodies of ICES.
2.6 The ACFM has taken an international
lead in developing the application of the Precautionary Approach
to fisheries management, and provides advice within a precautionary
context.
2.7 The ACFM advice goes directly to national
administrations and to the authorities who have sought the advice.
They include: the EU, the North East Atlantic Fisheries Commission,
the International Baltic Sea Fisheries Commission, the North Atlantic
Salmon Conservation Organisation, and the OSPAR Convention for
the Protection of the Marine Environment of the North East Atlantic.
Most of the UK fishing interests are covered through the Common
Fisheries Policy (CFP). The ACFM advice is the primary scientific
input for the European Commission's proposals for Total Allowable
Catches (TACs) for the following year.
2.8 Considerable monitoring and scientific
research is required to support the advisory process. The composition
of the catch is monitored at ports, on an annual basis, for size
and age by species and area of capture. At sea, the fish are sampled
directly by observers on board commercial vessels, especially
the small and young fish that will not be landed by the fleets.
Fish are also sampled by scientists on research vessels, to obtain
abundance estimates independent from commercial practices, and
in particular to obtain estimates of fish too small to be caught
by the fisheries. In Europe, this work is co-ordinated through
ICES. The numbers of fish in each stock can vary considerably
from year to year. As well as being affected by fishing, stocks
are affected by climate, by physical factors such as water movements,
and the environment, and by biological factors such as the supply
of food to larvae and adults, and predation by other animals in
the ecosystem. Consequently the underlying research covers a great
width of problems and disciplines.
2.9 The research undertaken includes: development
of new assessment and management methods; the basic biology of
fish and their biological interactions; the development of size
and species selective fishing gear; the impact of chemical and
radioactive contaminants on fish; the nature of disease in fish
and shellfish; the effect of the climate and seas on the abundance
and distribution of fish; the factors determining variability
in the numbers of young fish; the factors affecting sustainability
of stocks; and the effects of fisheries on the ecosystem itself.
2.10 Our knowledge of the sea and its ecological
processes is considerable, but still very limited given the complexity
of the systems involved. There is a continuing need for research
to improve our understanding of marine ecosystems, so that management
advice may take a broader perspective and is enhanced for the
future. It is important that research programmes not only address
issues of current concern but anticipate future problems.
2.11 In the UK, the research organisations
that are most involved with the assessement, research and advisory
process, for sea fish stocks, are The Centre for Environment,
Fisheries and Aquaculture Science (CEFAS—an Agency of MAFF),
Fisheries Research Services (FRS—an Agency of SOAEFD), and
The Agriculture and Environmental Science Division, of the Department
of Agriculture for Northern Ireland. The Sea Fish Industry Authority
is a Non-Departmental Public Body which undertakes economic and
technology research. Work is also commissioned from other research
organisations and universities, and there is increasing collaboration
between government research institutes and universities.
MONITORING
OF STOCKS
2.12 Monitoring of commercial catches provides
the basic information for assessment of fish stocks and management
of the fisheries. The data collected are: the size or age composition
of the catch; the catch-rates; and the absolute size of the catch.
Information is needed separately from each stock.
2.13 The size and age compositions of the
catch are determined by sampling fish at ports according to a
statistically designed programme. In the UK, over 50 stocks from
18 species are routinely sampled at ports. The weight of the catches
is monitored, and catch-rates are obtained from the records of
fishing vessels. Discards, the unwanted component of the catch
which is jettisoned at sea, are monitored by observers for some
of the most important stocks. As an example, figure (i) shows
the age composition of cod landed and discarded from UK vessels
fishing in the North Sea.
2.14 The UK fishery research vessels monitor
the stocks of fish at sea with a variety of methods including
fishing trawls and acoustics. Surveys are undertaken in the North
Sea, English Channel, Western Approaches, Irish Sea and West of
Scotland. All fish species are sampled. The information obtained
is the size and age composition of the catches, and the trawl
catch-rates. Port-based sampling observes only the fish landed.
In particular, at sea the research vessels sample the fish that
are too small and young to be landed by the commercial fleet.
The UK has important time-series of such information, which go
back to near the turn of the century and which can show how the
ecosystem has changed.
2.15 Figure (ii) illustrates the time series
of CEFAS research vessel catches of cod, from the North Sea, over
the period 1993 to 1997. It shows how numbers fluctuate from year
to year: few cod appeared at age 1 in 1993, 1995 and 1996. The
large size of the 1996 year-class can be seen. It is also evident
how quickly the numbers are reduced by fishing if the diagrams
are compared diagonally. Thus the large numbers at age 1 in 1994,
have declined significantly at age 2 in 1995 and are scarcely
evident at age 3 in 1996.
ESTIMATION
OF FISH
NUMBERS
2.16 Most stocks are assessed by a method,
developed in the UK, called virtual population analysis (VPA).
The relative abundance with age is determined from the sampled
research and commercial catch. If fish numbers decline rapidly
with age then the mortality due to fishing is high. Time series
data showing research and commercial catch-rates, for each age,
enable the trends in the stock to be seen. The weight of the estimated
total catch is used to relate the analysis of sample data to the
absolute abundance of each stock.
2.17 Some stocks are assessed by more direct
methods. These include: measuring the abundance of eggs which
a stock has produced in the plankton which can be evaluated in
relation to the eggs produced by a single fish (eg mackerel);
acoustic surveys to measure shoal size and density (eg herring);
and underwater visual surveys to count animals such as nephrops.
These methods provide estimates of stock size which avoid the
uncertainties inherent in data on commercial landings, but they
can be significantly more expensive to apply than VPA.
2.18 The quality of the assessments, and
the estimation of future catches, is dependent upon the accuracy
and precision of the statistics used in the assessments. ICES
has expressed its concern about the quality of catch and effort
data from most of the important fisheries in the ICES area. Under-reporting
and mis-reporting of commercial data make reliable assessments
more difficult. The most significant impact will tend to be on
the estimates of the absolute level of catches, whereas the trends
in the stocks, and the overall status of the stocks will be more
robust. For policy purposes it is usually the trends and overall
status which are more important.
2.19 Efforts are made to allow for inaccuracies
in commercial data when assessments and advice are prepared. In
addition, data from sources other than the commercial fleets,
such as data from research vessel surveys and egg-production surveys
are becoming increasingly important to the assessment process.
Assessment methods are also being developed that will enable a
fuller range of uncertainty to be expressed to managers.
SCIENTIFIC ADVICE
ON NEXT-YEAR'S
CATCHES
2.20 Scientific advice takes the form of
an estimate of the current stock position and the likely impact
of a number of policy options. These are expressed in terms of
the fishing mortality rate, F, which is a measure of the
proportion of the stock which is removed by fishing each year.
A fishing mortality rate of F = 1.0 means that about 60
per cent of the stock in the sea at the start of the year is removed
by fishing; for F = 0.5 about 35 per cent is removed. In
the example of North Sea cod given below, the present fishing
mortality is 0.64, which is equivalent to removing approximately
40 per cent of the stock per year. Estimated catches can be given
assuming fishing mortality is stable, or is increased, or decreased.
The abundance of the stock can also be estimated for the various
catch-options.
2.21 As an example, the table below shows
the options, and consequences, given by ACFM for North Sea cod
in 1997. The third line shows that if fishing effort was left
unchanged then the expected catch in 1998 would be 153 thousand
tonnes, leaving a mature biomass of 178 thousand tonnes. In the
event the Council adopted a TAC of 140 thousand tonnes—a
more cautious approach leaving scope for a bigger increase in
the mature biomass.
| Factor | F(98)
| SSB(98) | C(98)
| SSB(99) |
| 40 per cent reduction in F (96) |
0.38 | 173 | 101
| 226 |
| 20 per cent reduction in F (96) |
0.51 | 173 | 129
| 201 |
| No change in F (96) | 0.64
| 173 | 153 | 178
|
| 20 per cent increase in F (96) | 0.76
| 173 | 175 | 158
|
Notes
(i) F (96) and F (98) are the estimated
annual fishing mortality rates in 1996 and 1998.
(ii) SSB(98) and SSB(99) are the estimated weight of
mature biomass (spawning stock biomass) in thousands of tonnes
in January 1998 and 1999.
(iii) C(98) is the estimated weight of the catch, in
thousands of tonnes, in 1998.
THE VARIABILITY
OF SEA
FISH STOCKS
2.22 One of the dominant features of sea fisheries is
that the abundance and distribution of a stock can vary greatly,
due to natural causes, over short- and long-time scales.
2.23 Over the longer time scales, a classic case is the
change in relative abundance of the predominant pelagic species
of herring, pilchard and mackerel off the south-west of England
this century. Another example is the increased numbers of cod
in the North Sea over the period 1965 to 1985, which allowed catches
to treble (see figure (iii)).
2.24. One of the most important characteristics of many
stocks is a large year-to-year variability in recruitment. The
annual change in recruitment (technically the coefficient of variation)
is typically 50 per cent and over 100 per cent for some stocks.
The time series of recruitments of North Sea plaice, cod and haddock
are shown in figure (iv) and illustrate the high degree of variability.
2.25 The causes of such variability in fish recruitment
are poorly understood, but the variability is primarily driven
by climate and weather affecting the food supply to planktonic
fish larvae and their predators. Figure (v) gives an index of
the North Atlantic Oscillation (NAO), which is the difference
between climatic pressure systems at Greenland and the Azores
and which drives the major currents of the North Atlantic. For
the latter part of the time series the figure also plots an index
of the abundance of the copepod, Calanus, which is a major
food element of young North Sea roundfish. It can be seen that
the Calanus has followed the trend of NAO, and that Calanus
abundance (plotted on an inverted scale) has decreased as
the NAO has increased over the past few decades. Thus the underlying
changes in weather systems can be seen to be linked to trends
in the marine eco-system.
2.26 Current fishing rates are high, and incoming recruitments
are an important part of the catch. As a result the short-term
variability in recruitment has a major effect on both stocks and
catches because there are not enough older fish sufficiently to
buffer the variation. If fishing effort remained unchanged then,
at current fishing rates, catches of cod could be expected to
vary by over 10 per cent from year to year, and catches of haddock
by about 30 per cent as a result of recruitment variations alone.
2.27 These factors (ie the substantial short-term variability
in recruitment, and hence variability in stock size), make long-term
trends in the size of the stock difficult to determine. Such variability
may also give a false impression about sustainability. A stock
may show an increase for a short period due to one or two good
recruitments, even though the long-term trend is downward as a
result of serious over-exploitation.
THE STATUS
OF SEA
FISH STOCKS
2.28 Globally and in Community waters commercial fish
stocks are currently overfished. There are two forms of over-fishing:
recruitment over-fishing and growth over-fishing.
2.29 Most fish produce prodigious numbers of eggs—for
cod of the order of a million per spawning female per year. This
allows juvenile recruitment to be maintained even when fishing
is high and the spawning stock is much reduced. However, there
comes a point when the stock is so reduced that recruitments cannot
be maintained. This is termed recruitment over-fishing. Recruitment
over-fishing puts at risk the sustainability of the stock and
the fishery.
2.30 Figure (vi) below shows the relationship between
the production of young North Sea herring and the size of the
mature stock, each point representing the situation in a particular
year. The decline in recruitmentat low stock size is clear even
though the exact relationship from year to year moves unpredictably.
For many of our stocks, the limit at which recruitment declines
is not clear and thus the critical stock size where recruitment
starts to decline is not known for a large number of stocks.
2.31. ICES identifies safe biological limits for stocks.
Of the 35 assessed stocks of importance to the UK industry: 50
per cent are within safe limits; 30 per cent are below safe limits,
and 20 per cent are at about the limit.
2.32. Although stocks persistently subject to recruitment
over-fishing risk collapse there is no significant risk that the
commercial species will be driven to extinction. Rather, their
low numbers will mean closures of fisheries and long recovery
times for the depleted stocks.
2.33. Growth over-fishing occurs when stocks are fished
too heavily so that the fish get little chance to grow in size
and number and the yield from the fishery is depressed below the
optimum level. Fishing at lower rates would mean greater yields,
higher catch rates, less running costs, more fish in the sea,
and more stability for the industry.
2.34 Of the stocks in the north-eastern North Atlantic,
for which detailed information is available, most suffer from
growth-overfishing, many to a significant degree.
2.35 Rather different issues arise in relation to the
currently serious concern about the state of salmon stocks. Salmon
live at sea and return to rivers to breed. They are therefore
vulnerable to degradation of riverine habitats and to reductions
in growth and survival at sea. Salmon abundance has been declining
in the north-eastern North Atlantic, and recent UK catches have
been particularly low. The larger salmon, which stay at sea for
several years, have been especially affected. A range of environmental
factors is implicated in their decline.
TECHNICAL MANAGEMENT
MEASURES
2.36 Technical conservation measures are an important
element of fishery management. Technical measures address long-term
issues and include, closed areas and seasons, the selectivity
of fishing gears and minimum landing sizes. Most technical measures
are intended to improve the "exploitation pattern" of
thefleets and to make fishing more selective and so better targeted,
ie to discourage or reduce the capture of smalljuvenile fish and
the bycatch of non-target species. Of particular importance is
the need to match the gear selectivity to the target species.
This requires evaluation of appropriate mesh sizes and gear devices,
such as square mesh panels and sorting grids. Fisheries Departments
are engaged in a continuing programme of research into ways of
improving the conservation performance of fishing gears.
2.37 Closed areas are used extensively in fisheries management.
Fishing is restricted in large areas to protect young fish, such
as in the Plaice Box off the continental coast of the North Sea.
Protection of young fish will always be to the long-term benefit
of the fishery. However, protection of most fish during spawning
will be of little benefit to the stock and fishery, if the result
is to displace fishing effort so that the same level of catches
are taken elsewhere or at a different time.
SCIENCE SUPPORTING
FISHERIES MANAGEMENT
2.38 The research giving direct support to sea fisheries
management is covered under the Programmes for Marine Fisheries
and Salmon and Freshwater Fisheries. The Aquatic Environment programme
supports both protection of fish from environmental impacts and
the quality of marine environment per se.
2.39 Estimated expenditure by Government Fisheries Departments
on scientific support for fisheries and the aquatic environment
in 1997-98 was £36.8 million full economic cost (FEC). The
FEC is all costs including use of capital and overheads. Of this
£17.1 million was on work defined as R&D, and £19.7
million was on non-R&D work, such as monitoring and assessment.
The expenditure on the Marine Fisheries Programme was £15.8
million. The 1997-98 expenditure by Programme is tabulated below
(£million FEC).
| Programmes | Non-R&D
| R&D | £million Total
|
| Aquatic Environment | 5.875
| 5.835 | 11.710 |
| Aquaculture | 3.025 | 3.864
| 6.889 |
| Marine Fisheries | 9.861 |
5.916 | 15.777 |
| Salmon and Freshwater Fisheries | 0.947
| 1.529 | 2.476 |
| Total | 19.708 | 17.144
| 36.852 |
2.40 The Marine Fisheries Programme funds specific projects
under a range of Topics. The Topics include: fin-fish management;
shellfish management; multi-species biological interactions; physical
and biological controls on production; fish capture; and the impacts
of fishing on the ecosystem.
2.41 The Salmon and Freshwater Fisheries Programmes support
Topics on: assessment of salmonid stocks; factors affecting salmonid
stocks; and eels and non-migratory fish.
2.42 The Aquatic Environment and Aquaculture Programmes
are only of incidental relevance to the present discussion.
ECONOMIC RESEARCH
2.43 Most of the fisheries research is essentially biologically
based because of the way in which fisheries policy is currently
framed under the CFP. For example, the primary instrument for
fisheries management is TACS and quotas, and these require scientific
under-pinning. In addition the Multi-Annual Guidance Programmes
(MAGP) are under-pinned by a biological assessment of the size
of the fleet that the stocks can bear. Technical measures are
also principally informed by biological research.
2.44 However, Fisheries Departments do commission economic
research to support specific management issues. Such work has
recently included: an evaluation of the decommissioning schemes;
the possibility of charging for licences; research into the impact
of new fish markets on fish prices; a model to assess the impacts
of different EU-Norway mackerel agreements; and a bio-economic
model of the English Channel Fishery. The Sea Fish Industry Authority
(SFIA) also have their own economic research programme, and recent
projects have included: surveys of fishing costs and earnings;
the economic interpretation of the biological advice provided
by ACFM; and participation in EU projects to assess multi-annual
and multi-species TACs, and to look at the CFP beyond 2002. These
projects are reported to the SFIA Economics Advisory Committee
which comprises representatives from the industry and Fisheries
Departments. University Departments and private consultancies
are also active in producing economic studies (sometimes under
contract with the European Commission) which are of use to UK
fisheries managers.
FISHERY RESEARCH
VESSELS
2.45 Fishery research vessels are specialised facilities.
They are designed to permit a range of scientific operations,
including: fishing; deployment and towing of sensitive electronic
equipment; and sampling and experimentation at sea. Fishery surveys
provide information independent of the commercial fleet, and on
a wider range of species and size of fish. The results from surveys
are sensitive to the vessel used. Consequently a single dedicated
vessel is required over a period of years in order to give a consistent
time series of survey data.
2.46 The following Table describes the UK fleet of fishery
research vessels.
| Organisation | Vessel Name
| Date Built | Length (M)
|
| CEFAS | RV Cirolana | 1970
| 72 |
| CEFAS | RV Corystes | 1988
| 53 |
| DANI | RV Lough Foyle | 1974*
| 44 |
| FRS | FRS Scotia | 1998
| 69 |
| FRS | FRS Clupea | 1969
| 32 |
| *acquired 1989. | |
| |
2.47 RV Cirolana has outlived its operational life, and
MAFF has recently announced its intention to fund a new fishery
research vessel. The RV Lough Foyle and the FRS Clupea are also
nearing the end of their operational lives.
CO -ORDINATION
OF FISHERIES RESEARCH
2.48 There is co-ordination of fisheries research at
national and international level to ensure that key issues are
being covered and that unnecessary duplication is avoided.
2.49 The Fisheries Science Customer Group (FSCG) co-ordinates
work between Fisheries Departments. Membership comprises Fisheries
Secretaries from MAFF and SOAEFD, the Under-Secretary (Environment)
from MAFF, and the Chief Scientist from DANI. The FSCG meets annually.
2.50 The Agriculture, Food and Fisheries Research Funders
Group co-ordinates research between Departments and Research Councils.
It meets annually and has a membership of DANI, MAFF, SOAEFD,
WOAD, BBSRC, NERC and the Forestry Commission. There is also co-ordination
with DETR on marine research.
2.51 The Management Group of Directors (MGD) comprises
the Chief Executives and Directors of the government's fisheries
laboratories. They meet to ensure that work is being done effectively
and efficiently, between and within institutes.
2.52 ICES co-ordinates a great deal of the international
fisheries work. All the main fisheries surveys are conducted to
agreed plans, and results feed directly to ICES Working and Advisory
Groups. ICES' Science Groups review and co-ordinate international
research plans.
COMMUNICATION
2.53 Communication of results is important in giving
the fishing industry and the public confidence in the scientific
advice.
2.54 Fisheries scientists are encouraged to disseminate
their results to both a scientific and lay audience. As well as
publishing results in the scientific literature, the fisheries
institutes produce a range of publications.
2.55 Significant efforts are also put into face to face
discussions. Fisheries scientists meet with the fishing industry
during the year both locally and nationally to hear their views
and to discuss the stock assessments. Of particular importance
are meetings in November when the advice from ICES' ACFM is explained
to the industry: this advice is central to the setting of TACs
by Fisheries Ministers in December. The ACFM advice is subsequently
published by ICES.
2.56 There are also many other opportunities for contacts.
Fisheries scientists frequently work with members of the fishing
industry at ports, when sampling discards, when chartering commercial
fishing vessels, and when invited to observe commercial operations.
Fisheries scientists and fishermen meet regularly within the UK
Fisheries Conservation Group which reviews technical conservation
measures. While there is always scope for disagreement—not
least about the state of the stocks—the relationship between
fishermen and scientists is usually positive and constructive.
The National Federation of Fishermen's Organisations has recently
suggested to the European Commission that the meetings between
industry and scientists, held in the UK prior to the scientists
undertaking assessments, may be a useful model for other Member
States.
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