www.gov.scot/marinescotland
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Introduction
One of the principal roles of the Marine Scotland
Fisheries Management Programme is to
scientifi cally assess the health and status of fi sh
and shellfi sh stocks important ot Scotland. The
results of these assessments are used to provide
advice to the Scottish Government in order to
help them manage Scottish fi sheries. This leafl et
describes the processes leading to advice (see
summary Fig. 1).
Gathering the data
Marine Scotland runs one of the largest fi sh and
shellfi sh sampling programmes in Europe. This
is made up of three different components, each
taking place all year round. The components
are: gathering scientifi c data about fi sh and
shellfi sh landed at Scottish ports (the Market
Sampling Programme); gathering scientifi c data
about fi sh and shellfi sh caught by commercial
fi shing vessels before it is landed or discarded
(the Observer Programme); and conducting
scientifi cally-designed surveys of fi sh and
FISHERIES MANAGEMENT PROGRAMME ASSESSING SCOTTISH FISH AND SHELLFISH STOCKS
shellfi sh stocks using dedicated research vessels
owned by Marine Scotland and chartered
commercial fi shing vessels (the Research Vessel
Survey Programme). Figures 2, 3, 4 and 5 give
more details about these programmes.
Once the data are gathered, either ashore or at
sea, they are checked for accuracy and quality,
combined with information gathered by Marine
Scotland Compliance (information on the total
amount of fi sh and shellfi sh landed across
Scotland), and stored using computer databases.
Assessing the stocks
When the data have been collected and checked,
scientists use the information to estimate the
size of fi sh and shellfi sh stocks, and how they are
changing. For stocks of fi sh and shellfi sh which
inhabit areas larger than just Scottish waters,
or are fi shed by international fi shing fl eets, our
information is pooled with that gathered by our
European colleagues (see Fig. 6).
FIGURE 1. A SUMMARY OF THE PROCESSES UNDERTAKEN BY THE FISHERIES MANAGEMENT PROGRAMME WHICH RESULTS IN ADVICE TO SCOTTISH AND UK GOVERNMENTS, AS WELL AS INTERNATIONAL BODIES, REGARDING THE HEALTH AND STATUS OF SCOTTISH FISH AND SHELLFISH STOCKS. THE THREE MAIN SAMPLING PROGRAMMES PRODUCE INFORMATION ABOUT OUR STOCKS WHICH IS THEN CHECKED FOR QUALITY, COMBINED WITH INFORMATION FROM OTHER SOURCES, INCLUDING INTERNATIONAL PARTNERS, FED INTO A SCIENTIFIC ASSESSMENT PROCESS, THE RESULTS OF WHICH ARE THEN USED AS THE BASIS OF PROVIDING ADVICE. RESEARCH IS CONTINUALLY UNDERWAY TO IMPROVE ALL STEPS IN THIS PROCESS.
ADVICE RESEARCH
ASSESSMENT
DATA COLLATION
MARKET SAMPLING
OBSERVED SAMPLING
RESEARCH VESSELS SURVEYS
TOPIC SHEET NUMBER 22 V1
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Complex calculations are then performed which
estimate such things as the total abundance of a
particular species in different areas, such as the
North Sea and west of Scotland. These abundance
estimates are calculated for each different age of
fi sh in a stock. Using this information, along with
knowledge about the biology of each species (for
example, how fast it grows, how old it is when it
sexually matures, how many of the species die
through natural causes each year including being
eaten by other species) our scientists estimate
Stock AssessmentICES Workng Groups
Fish Stocks
Data Collection
RV surveys
Annual TAC Setting Cycle
Council of MinistersAgree TACs
ManagersEC - DGXIV
NEAFCSGMD
Scientific AdviceACFMSTECF
Stock Assessment
ICES Workng Groups
Fishing Fleets
Data CollectionMarket sampling
Observer samplingRV surveys
Allocation Key
Allocates quotas to member states
Year starts
Demersal / Pelagic2,000 vessel landings330,000 fish lengths66,000 fish aged
Shellfish500 vessel landings230,000 lengths
Sub-sample of Scottish Landings
Sub-sample Lengths
Assessment
Sub-sample Aged
Landed numbers-at-age(length) by Area
by Gear by Month
Total Landed Weights
Fish Stocks
how many fi sh and shellfi sh are being taken
in the fi sheries, and they also predict how fi sh
stocks will change in the future given different
levels of fi shing.
Providing scientifi c advice
The estimates of the current and past status
and trends in the different aspects of our fi sh
and shellfi sh stocks, as well as the predictions
of future status and trends, are then used to
provide scientifi c advice to managers of our
fi sheries. Figure 7 summarises the annual round
of fi sheries management in Europe at the current
time.
Increasingly, we are using scientifi c information
and assessments based on the FRS Fisheries
Management sampling programme to provide
advice not only to the Scottish Government, but
also to the Scottish fi shing industry, the European
fi shing industry through Regional Advisory
Councils (RACs) and the European Union through
the International Council for the Exploration of
the Sea (ICES), and the European Commission’s
Scientifi c, Technical and Economic Committee for
Fisheries (STECF). This advice is also widening
to include aspects of the health of the marine
ecosystem in general, and the status of marine
habitats and biodiversity, of which fi sh and
shellfi sh are an integral part.
FIGURE 6. A TYPICAL WORKING GROUP OF THE INTERNATIONAL COUNCIL FOR THE EXPLORATION OF THE SEA (ICES) WHERE FRS SCIENTISTS JOIN INTERNATIONAL COLLEAGUES TO EXCHANGE DATA, AND REACH A SCIENTIFIC CONSENSUS ON THE ASSESSMENT AND PREDICTIONS OF THE STATUS AND HEALTH OF EUROPEAN FISH STOCKS.
Survey Name Target Species Area Timing Frequency
Pelagic
Mackerel Egg Survey Mackerel West of Britain Apr-May Triennial
Herring Acoustic Survey Herring North Sea Jun-Jul Annual
Herring Acoustic Survey Herring West of Scotland Jul Annual
MIK Juvenile Herring Survey Herring North Sea Jan-Feb Annual
Demersal
IBTS NSQ1 Demersal fi sh North Sea Jan-Feb Annual
IBTS WCQ1 Demersal fi sh West of Scotland Mar Annual
IBTS Q3 Survey Demersal fi sh North Sea Aug Annual
IBTS Q4 Survey Demersal fi sh (and mackerel) West of Scotland Nov-Dec Annual
Anglerfi sh Anglerfi sh and Megrim Northern shelf April Annual
Nephrops (langoustine)
Nephrops TV Survey Nephrops (inshore) West of Scotland (Sea lochs) Jan Annual
Nephrops TV Survey Nephrops (offshore) North Sea / west coast Jun Annual
Nephrops TV Survey Nephrops (inshore) East of Scotland Jul-Aug Annual
Other Shellfi sh
Shetland Coast Scallop Survey Scallop Shetland Jan-Mar Annual
East Coast Scallop Survey Scallop Scottish east coast Jun-Jul Annual
West Coast Scallop Survey Scallop Scottish west coast Apr-May Annual
Cockle (Shore based) Cockle and Macoma Solway Firth August Annual
Others
Rockall / Deepwater Survey Demersal fi sh Rockall / Shelf Edge Sep Annual
North Sea Sandeel Survey Sandeel North Sea Nov-Dec Annual
BW International Survey Blue whiting West UK Mar Annual
FIGURE 2. THE FRS RESEARCH VESSEL SURVEY PROGRAMME – DETAILS OF THE 19 SURVEYS UNDERTAKEN USING RESEARCH VESSELS AND CHARTERED COMMERCIAL VESSELS. THE PRINCIPAL SPECIES TARGETED BY EACH SURVEY ARE SHOWN. DEMERSAL SPECIES INCLUDE COD, HADDOCK, SAITHE, WHITING AND ANGLERFISH. THE SPECIES TARGETED BY THE RESEARCH VESSEL SURVEY PROGRAMME ARE ALSO THE PRINCIPAL SPECIES SAMPLED IN THE MARKET SAMPLING AND OBSERVER PROGRAMMES. SURVEYS HIGHLIGHTED IN BLUE ARE STIPULATED WITHIN THE EU DATA COLLECTION REGULATION (DCR).
(NOTE: IBTS – INTERNATIONAL BOTTOM TRAWL SURVEY)
FIGURE 3. THE RESEARCH VESSEL SURVEY PROGRAMME – THE TRACK OF THE RESEARCH VESSEL SCOTIA IN A TYPICAL YEAR (2004). OVER THIS YEAR SCOTIA COVERED 52,000 NAUTICAL MILES AND WAS AT SEA FOR 285 DAYS. MANY DIFFERENT SURVEYS CAN BE SEEN, FOR EXAMPLE; MACKEREL EGG SURVEY – THE BROAD SCALE SURVEY DOWN WESTERN SHELF EDGE TO THE SOUTH OF IRELAND; HERRING ACOUSTIC SURVEY – FINE SCALE GRID OF LINES EAST AND WEST OF SHETLAND; THE INTERNATIONAL BOTTOM TRAWL SURVEY (IBTS) – THE LARGE SCALE PATTERN OF SAMPLING IN THE NORTH SEA.
FIGURE 5. THE OBSERVER PROGRAMME – SCIENTISTS SAIL ON BOARD COMMERCIAL VESSELS IN ORDER TO OBTAIN BIOLOGICAL DATA FROM CATCHES (THIS
INCLUDES FISH THAT MAY EVENTUALLY BE LANDED AS WELL AS FISH THAT MAY BE DISCARDED). THE NUMBERS INDICATE A TYPICAL YEAR’S
SAMPLING REGIME. THE MAP INDICATES A TYPICAL ANNUAL SAMPLING DENSITY FOR DEMERSAL OBSERVER TRIPS.
FIGURE 4. THE MARKET SAMPLING PROGRAMME – SCIENTISTS VISIT THE PRINCIPAL MARKETS AND LANDING POINTS OF COMMERCIAL FISH AND SHELLFISH IN SCOTLAND. LANDINGS ARE CAREFULLY SUB-SAMPLED IN ORDER TO OBTAIN A REPRESENTATIVE PICTURE FROM DIFFERENT AREAS, SPECIES AND FISHING GEAR TYPES. BIOLOGICAL INFORMATION IS GATHERED. FOR EXAMPLE, FISH SAMPLES ARE MEASURED FOR LENGTH, AND THEIR EAR BONE (OTOLITH) REMOVED IN ORDER TO DETERMINE THEIR AGE (OTOLITHS HAVE ANNUAL GROWTH RINGS THAT CAN BE COUNTED). THE NUMBERS INDICATE A TYPICAL YEAR’S SAMPLING REGIME.
Demersal / Pelagic2,000 vessel landings330,000 fish lengths66,000 fish aged
Shellfish500 vessel landings230,000 lengths
Sub-sample of Scottish Landings
Sub-sample Lengths
Assessment
Sub-sample Aged
Landed numbers-at-age(length) by Area
by Gear by Month
Total Landed Weights
150 fishing vessels200,00 fish lengths13,500 fish aged38,000 shellfish lengths
ASSESSMENT
Discarded numbers at-age
by area by gear by quarter
Landed numbers at-age
by area by gear by month
CATCHnumbers at-age by area by
gear species by month