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