To maintain the reproductive capacity of stocks, each stock’s spawning biomass should be at or above the level capable of producing maximum sustainable yield. The proportion of marine fish stocks (including Nephrops) subject to quota management and achieving this goal increased from 28% in 1990 to 56% in 2016.

Background

Europe has a long history of commercially exploiting marine fisheries resources. Historically, the overexploitation of finfish and shellfish stocks led to the depletion of stock abundances. In response, a range of national and international management measures to protect and conserve marine fisheries resources were implemented. Measures that help to protect the Spawning Stock Biomass (referred to as ‘SSB’) include Minimum Conservation Reference Sizes and technical regulations on fishing gears to ensure that stocks are exploited sustainably at full reproductive capacity with a stable population structure. Achieving Good Environmental Status and maintaining stocks within safe biological limits requires that the spawning stock biomass of each stock is at or above the level capable of producing Maximum Sustainable Yield, this level is denoted ‘MSY Btrigger’.

Stocks are aggregated within UK waters of the North East Atlantic Ocean to assess the overall proportion of stocks with spawning stock biomass estimates above or equal to MSY Btrigger. Since marine fish (including Nephrops) are subject to international quota and national shellfish stocks (crab, lobster, and scallop) are not, these two groups are considered separately. However, since there are currently no accepted reference points for national shellfish stocks, this indicator assessment can only evaluate temporal trends in the spawning stock biomass estimates of marine fish stocks with respect to MSY Btrigger. The objective is to increase the proportion of stocks with spawning stock biomass at or above MSY Btrigger and reduce to zero the number of stocks that have unknown status relative to maximum sustainable yield reference points.

Further information

Political commitments to achieve the sustainable exploitation of marine fisheries resources have been specified in two major pieces of European environmental legislation. Firstly, the European Union’s Common Fisheries Policy was launched in 1970 with the objective of ensuring that fishing is environmentally, economically, and socially sustainable (European Commission, 2013). An important component of the Common Fisheries Policy is that stocks should be exploited sustainably to provide the maximum sustainable yield, defined the maximum catch that can be taken annually without reducing stock productivity, by 2020. Secondly, the European Union’s Marine Strategy Framework Directive was established in 2008 to protect the marine environment and ensure the sustainable use of marine goods and services by achieving Good Environmental Status of marine waters by 2020 (EU Commission, 2008). Fulfilling the Marine Strategy Framework Directive’s objective of achieving Good Environmental Status is consistent with the Common Fisheries Policy requirement that spawning stock biomass levels are at or above the level capable of generating maximum sustainable yield. The Marine Strategy Framework Directive requires that “populations of all commercially exploited finfish and shellfish are within safe biological limits, exhibiting a population age and size distribution that is indicative of a healthy stock” (EU Commission, 2008).

Most commercially exploited fish and Nephrops (Norway lobster) stocks in Europe are monitored and assessed by the International Council for the Exploration of the Sea (ICES) and are subject to internationally agreed quotas. In UK waters, national assessments are undertaken for crab and lobster stocks (Cefas 2015a; 2015b; Mesquita and others, 2016) and scallops (Dobby and others, 2012; ICES 2015). Fisheries management advice for assessed stocks is based on estimates of fishing mortality and biomass relative to reference points for long-term sustainability (ICES, 2016). Reference points include the spawning stock biomass trigger point (MSY Btrigger), which is considered the lower bound in the natural fluctuation of spawning stock biomass around the level that results from fishing at maximum sustainable yield for a long time. Assessment methods vary among stocks according to the quantity and quality of the available data. All available data for UK stocks are considered equally in the indicator assessment.

Marine Fish (Quota) Stocks

Stocks considered here are given in Table 1. Assessed stocks have been classified by the International Council for the Exploration of the Sea into one of six data categories depending on the availability of data collected under the European Union Data Collection Framework (ICES, 2012). The categorisation of the stocks reflects the decreasing availability of data, and conclusions on fishing mortality and stock biomass are typically less certain as the category increases.

Table 1. Marine fish (quota) stocks of UK interest.

Stock Description

Data type

Assessment method

Method description

Nephrops in Divisions IVb and IVc Botney Gut/Silver Pit (FU5)

Data-Limited

Data-limited method for Nephrops

Potential harvest rates given habitat

North Sea Megrim in Divisions IVa and VIa

Data-rich

Bayesian state-space biomass dynamic model

Fully quantitative

Whiting in Division VIb (Rockall)

Data-Limited

NA

NA

Cod in VIb Rockall Plateau

Data-Limited

NA

NA

Pollack (Pollachius pollachius) in Subareas VI-VII (Celtic Seas and the English Channel)

Data-Limited

DCAC (Depletion-Corrected Average Catch)

Commercial landings trend

Sprat in Subarea VI and Divisions VIIa-c and f-k (Celtic Sea and West of Scotland)

Data-Limited

NA

NA

Black-bellied anglerfish in Divisions VIIb,k, and VIIIa,b,d

Data-Limited

Survey CPUE and landings

Trends based

Anglerfish in Subareas IV and VI and Division IIIa

Data-Limited

Survey CPUE and landings

Trends based

White anglerfish in Divisions VIIb,k, and VIIIa, b, d

Data-Limited

Survey CPUE and landings

Trends based

Ling in Subareas VI-IX, XII, and XIV, and in Divisions IIIa and IVa

Data-Limited

Commercial CPUE and landings

Trends based

Megrim in Division VIb

Data-Limited

Survey CPUE and landings

Trends based

Megrim in Divisions VIIb,k and VIIIa, b, d

Data-Limited

Statistical catch at age model

Trends based

Plaice in Divisions VIIf,g

Data-Limited

Survey-based assessment

Survey-based trends

Whiting in Division VIIa

Data-Limited

Survey-based assessment

(SurbaR)

Survey-based trends

Cod (Gadus morhua) in Subarea IV and Divisions VIId and IIIa West (North Sea. Eastern English Channel. Skagerrak)

Data-rich

Age-based analytical assessment (SAM)

Fully quantitative

Cod (Gadus morhua) in Divisions VIIe-k (Western English Channel and Southern Celtic Seas)

Data-rich

Age-based analytical assessment (XSA)

Fully quantitative

Cod (Gadus morhua) in Division VIIa (Irish Sea)

Data-rich

Analytical assessment (SAM)

Fully quantitative

Cod (Gadus morhua) in Division VIa (West of Scotland)

Data-rich

Analytical age-based assessment (TSA)

Fully quantitative

Spurdog in the Northeast Atlantic

Data-rich

Age-length and sex-structured model (De Oliveira et al., 2013)

Fully quantitative

Haddock in Subarea IV and Divisions IIIa West and VIa (North Sea. Skagerrak and West of Scotland)

Data-rich

Age-based analytical assessment (TSA)

Fully quantitative

Haddock in Divisions VIIb.c.e-k

Data-rich

Age-Structured Assessment Programme (ASAP)

Fully quantitative

Haddock in Division VIIa (Irish Sea)

Data-Limited

SURBA analysis based on survey information

Survey-based trends

Haddock in Division VIb (Rockall)

Data-rich

Analytical age-based assessment (XSA)

Fully quantitative

Herring in Subarea IV and Divisions IIIa and VIId (North Sea autumn spawners)

Data-rich

Age-based analytical assessment (SAM)

Fully quantitative

Herring (Clupea harengus) in Divisions VIa and VIIb.c (West of Scotland. West of Ireland)

Data-rich

Age-based analytical assessment (SAM)

Fully quantitative

Herring in the Celtic Sea and South of Ireland

Data-rich

Age-based analytical assessment (ASAP)

Fully quantitative

Herring in Division VIIa North of 52° 30N (Irish Sea)

Data-rich

Age-based analytical assessment (FLSAM)

Fully quantitative

Herring in Subareas I. II. V and Divisions IVa and XIVa (Norwegian spring-spawning herring)

Data-rich

Statistical assessment model (XSAM)

Fully quantitative

Hake in Division IIIa. Subareas IV. VI and VII and Divisions VIIIa.b.d (Northern stock)

Data-rich

Length-based model (SS3)

Fully quantitative

Horse mackerel (Trachurus trachurus) in Divisions IIa. IVa. Vb. VIa. VIIa-c. e-k. VIII (Western stock)

Data-rich

Age-based analytical assessment (Linked Separable Adapt VPA)

Fully quantitative

Mackerel in the Northeast Atlantic (combined Southern. Western and North Sea spawning components)

Data-rich

Age-based analytical model (SAM)

Fully quantitative

Nephrops in Division VIa (North Minch. FU 11)

Data-rich

Underwater TV survey combined with yield-per-recruit analysis from length data

Fully quantitative

Nephrops in Division VIa (South Minch. FU 12)

Data-rich

Underwater TV survey combined with yield-per-recruit analysis from length data

Fully quantitative

Nephrops in the Firth of Clyde + Sound of Jura (FU 13)

Data-rich

Underwater TV survey combined with yield-per-recruit analysis from length data

Fully quantitative

Nephrops in Division VIIa (Irish Sea East. FU 14)

Data-rich

Underwater TV survey combined with yield-per-recruit analysis from length data

Fully quantitative

Nephrops in Division VIIa (Irish Sea West. FU 15)

Data-rich

Underwater TV survey combined with yield-per-recruit analysis from length data

Fully quantitative

Nephrops in Division VIIb.c.j.k (Porcupine Bank. FU 16)

Data-rich

Underwater TV survey combined with yield-per-recruit analysis from length data

Fully quantitative

Nephrops in Division IVb (Farn Deeps. FU 6)

Data-rich

Underwater TV survey combined with yield-per-recruit analysis from length data

Fully quantitative

Nephrops in Division IVa (Fladen Ground. FU 7)

Data-rich

Underwater TV survey combined with yield-per-recruit analysis from length data

Fully quantitative

Nephrops in Division IVb (Firth of Forth. FU 8)

Data-rich

Underwater TV survey combined with yield-per-recruit analysis from length data

Fully quantitative

Nephrops in Division IVa (Moray Firth. FU 9)

Data-rich

Underwater TV survey combined with yield-per-recruit analysis from length data

Fully quantitative

Plaice in Division VIId (Eastern Channel)

Data-rich

Age-based analytical assessment (Aarts and Poos, 2009)

Fully quantitative

Plaice in Division VIIe (Western Channel)

Data-Limited

Age-based analytical assessment (XSA)

Survey-based trends

Plaice in Division VIIa (Irish Sea)

Data-Limited

Age-based assessment model (Aarts and Poos, 2009)

Survey-based trends

Plaice Subarea IV (North Sea)

Data-rich

Age-based analytical assessment (XSA)

Fully quantitative

Roundnose grenadier (Coryphaenoides rupestris) in Subareas VI and VII, and Divisons Vb and XIIb

Data-rich

Bayesian surplus production model covering only Division 5.b and subareas 6 and 7

Fully quantitative

Saithe in Subarea IV (North Sea) Division IIIa West (Skagerrak) and Subarea VI (West of Scotland and Rockall)

Data-rich

Age-based analytical assessment (SAM)

Fully quantitative

Sole in Divisions VIIf. g (Celtic Sea)

Data-rich

Age-based analytical assessment (XSA)

Fully quantitative

Sole in Division VIId (Eastern Channel)

Data-rich

Age-based analytical assessment (XSA)

Fully quantitative

Sole in Division VIIe (Western Channel)

Data-rich

Age-based analytical assessment (XSA)

Fully quantitative

Sole in Division VIIa (Irish Sea)

Data-rich

Age-based analytical assessment (XSA)

Fully quantitative

Sole in Subarea IV (North Sea)

Data-rich

Statistical catch-at-age model with flexible selectivity functions

Fully quantitative

Sprat in Subarea IV (North Sea)

Data-rich

Age-based analytical assessment (SMS)

Fully quantitative

Blue whiting in Subareas I-IX. XII and XIV (Combined stock)

Data-rich

Age-based analytical assessment (SAM)

Fully quantitative

Whiting Subarea IV (North Sea) and Division VIId (Eastern Channel)

Data-rich

Age-based analytical assessment (XSA)

Fully quantitative

Whiting in ICES Division VIIb. c. e-k

Data-rich

Age-based analytical assessment (XSA)

Fully quantitative

Whiting in Division VIa (West of Scotland)

Data-rich

Age-based analytical assessment (TSA)

Fully quantitative

National Shellfish Stocks:

Stocks considered here are given in Table 2. National assessments are completed every three years. Currently, biomass reference points are not available (Cefas 2015a, 2015b; Dobby and others, 2012; Mesquita and others, 2016; ICES 2015).

Table 2. National shellfish stocks of UK interest. The King scallops stocks (*) are proposed stock units (ICES, 2016).

Species

Stock

Species

Stock

Velvet crab

Necora puber

Clyde

Lobster

Homarus gammarus; Palinurus elephas

East Anglia

East Coast

Northumberland and Durham

Hebrides

Southwest

Mallaig

Yorkshire and Humber coast

North Coast

Clyde

Orkney

East Coast

Papa Bank

Hebrides

Shetland

Mallaig

South East

North Coast

South Minch

Orkney

Sule

Papa Bank

Ullapool

Shetland

Brown crab

Cancer pagarus

Clyde

South East

East Coast

South Minch

Hebrides

Sule

Mallaig

Ullapool

North Coast

King scallops

Pecten maximus*

Irish Sea

Orkney

 

Cardigan Bay

Papa Bank

 

Celtic Sea

Shetland

 

Western Channel N

South East

 

Western Channel S

South Minch

 

Eastern Channel N

Sule

 

Central North Sea

Ullapool

 

West of Kintyre

Celtic Sea

 

Northwest

Central North Sea

 

Northeast

Southern North Sea

 

Shetland

Western Channel

 

Orkney

Queen Scallops

Aequipecten opercularis

West of Scotland and Irish Sea (VIa and VIIa)

 

Clyde

 

East Coast

Assessment method

A total of 57 marine fish stocks (including Nephrops) and 59 national shellfish stocks of UK interest in the North East Atlantic Ocean were included in the assessment of spawning stock biomass indicators.

Fishing pressure metrics were estimated since 1990 because there were great changes prior to this in fisheries management aims and objectives (Lassen and others, 2014). A new advisory framework was adopted in 1976, precautionary approach reference points were not formally adopted until the 1990s, and maximum sustainable yield much later (Lassen and others, 2014). Following an initial analysis, national shellfish and marine fish (including Nephrops) communities were separated given the differing management regimes for national stocks and those with internationally agreed quotas, contrasting temporal patterns in the metrics and differing levels of maturity in the stock assessment procedures.

Data were lacking for the reference point for national shellfish stocks, so trends in this indicator could be assessed only through the spawning stock biomass of marine fish stocks.

Marine fish (quota) stocks

Stocks ranged from ICES Data Categories 1 to 6 and were located in the Celtic Seas and Greater North Sea. Category 1 is considered data-rich, and all other categories are data-limited. The stocks comprise a very large proportion of the total landings by UK vessels (> 90%).

ICES has developed maximum sustainable yield and precautionary approaches to provide fisheries management advice based on data availability and the current state of knowledge (ICES, 2016a). Stocks in ICES Data Categories 1 and 2 have full analytical assessments that provide estimates of spawning stock biomass that can be compared to spawning stock biomass trigger points consistent with ICES maximum sustainable yield advice (for example, ICES, 2016b). Spawning stock biomass trigger point estimates, however, require a relatively high level of data and knowledge of stock dynamics. Assessments for Category 3 and Category 4 stocks provide estimates of spawning stock biomass from survey indices or catch time-series that can be related to proxies of Maximum Sustainable Yield or precautionary reference points (ICES, 2016c). Data-limited stocks in Categories 5 and 6 have insufficient information to estimate spawning stock biomass with a high degree of certainty and management advice is based on the precautionary approach (ICES, 2013).

The preliminary analysis focused on estimating stock size relative to spawning stock biomass trigger points for stocks of UK interest. Reference points (Maximum Sustainable Yield Btrigger) and time-series of annual spawning stock biomass estimates were extracted from the ICES Standard Graphs database and an online interface for stock assessment . An annual stock size metric for each stock was estimated by dividing annual spawning stock biomass estimates by the time-series invariant MSY Btrigger. For the remaining data-limited stocks of UK interest, without time-series of annual spawning stock biomass estimates and/or MSY Btrigger points, assessments could not be made, and stocks were classified as unknown.

National shellfish stocks

Crab and lobster assessments are the most developed of the shellfish assessments and provide data on spawning stock biomass by sex using Length Cohort Analysis (Cefas 2015a, 2015b; Mesquita and others, 2016). Stock assessments for scallops are still in development, but great progress has been made in recent years with well-defined stock units in Scottish waters and preliminary stock units for English and Welsh waters under discussion (Dobby and others, 2012; ICES 2015).

Indicator

The indicator is estimated annually by dividing the total number of stocks with spawning stock biomass greater than MSY Btrigger by the number of unique stocks present in the dataset (irrespective of whether reference points and time series are available for each stock). In this way, the number of stocks over time is kept constant despite changes in assessment procedures. The community-specific indicator is thus the annual proportion of marine fish stocks of UK interest or national shellfish stocks with spawning stock biomass above MSY Btrigger.

Results

Findings in the UK Initial Assessment in 2012

Previously assessments were made by subregion (Greater North Sea, Celtic Seas) for those stocks for which ICES provided full assessments (including reference points) and for which the UK contributed to through the Data Collection Framework. These assessments considered the precautionary approach reference point (known as ‘Bpa’) as the target for spawning stock biomass in line with ICES advice at the time. For national shellfish stocks, an indicator assessment could not be reported due to data limitations. Thus Nephrops (Norway lobster) was the only shellfish species that contributed quantitatively to the initial assessment.

For the Greater North Sea, 91% of analytically assessed fish stocks (excluding data-limited stocks) were considered at Good Environmental Status in terms of reproductive capacity (HM Government, 2012). Four of the nine Nephrops functional units in the North Sea were assessed and of these 75% met Good Environmental Status for the reproductive capacity of stocks.

For the Celtic Seas, 72% of analytically assessed fish stocks (excluding data-limited stocks) met Good Environmental Status for the reproductive capacity of stocks (HM Government, 2012). All four of the eight Nephrops functional units assessed met Good Environmental Status in relation to reproductive capacity.

Latest findings

The indicator has been altered and now includes more stocks than before, including those of unknown status. All national shellfish stocks were unknown relative to maximum sustainable yield reference points. A steady increase in the proportion of marine fish stocks with spawning stock biomass above or equal to the level capable of producing Maximum Sustainable Yield (MSY Btrigger) was evident since 1990 (Figure 1). Of the 57 marine fish (quota) stocks, 28% achieved spawning stock biomass above or equal to MSY Btrigger in 1990, and this proportion gradually increased to reach 56% in 2016. The proportion of marine fish stocks with spawning stock biomass estimates below MSY Btrigger remained relatively stable over time, peaking at 40% in 2000 and again in 2007 then subsequently declining to 26% in 2015 and 23% in 2016. Data-limited marine fish stocks without annual spawning stock biomass estimates and/or MSY Btrigger points decreased from 42% in 1990 to 14% between 2005 and 2014, then rose slightly to 21% in 2016. This rise in recent years is due to the scheduling of assessment updates and acknowledgements by working groups that assessment methods required reassessment (known as benchmarking).

Overall, the assessment illustrates a transition towards achieving all populations of commercial fish within safe biological limits by 2020. Since 2012, on average 59% of the internationally managed marine fish (quota) stocks were sustained at full reproductive capacity indicative of healthy stocks. However, of the combined set of shellfish and marine fish stocks, 61% remained unknown in 2015.

Figure 1. The proportion of marine fish (quota) stocks of UK interest exploited with respect to MSY Btrigger (the spawning stock biomass level capable of producing Maximum Sustainable Yield).

Further information

Progress towards achieving populations of commercial fish within safe biological limits by 2020

The stocks considered here are fished not only by UK vessels but also by fleets from other countries. The proportion of the total international landings that arises from fish stocks that are sustained at or above MSY Btrigger has increased to > 90% since 2009 (Figure 2). This demonstrates that the majority of landings are taken from fish stocks that are in a healthy state.

Figure 2. The proportion of total international catch of stocks of UK interest partitioned among assessment status with respect to MSY Btrigger (the spawning stock biomass level capable of producing Maximum Sustainable Yield).

A high degree of confidence exists in the assessment of spawning stock biomass for many marine fish stocks of UK interest. The proportion of marine fish stocks with unknown status decreased gradually to 14% in 2005 and remained around this level thereafter. Fluctuations are evident in the final two years of the assessment (16% in 2015 and 21% in 2016) due to the scheduling of assessment updates and acknowledgements by working groups that assessment methods required reassessment (known as benchmarking). The proportion of data-limited stocks classified as unknown in the assessment should decline as data availability increases and assessment methods improve in the future. The status of each stock in 2015 and 2016 is given in Tables 3 and 4 respectively.

Table 3. Marine fish (quota) stocks of UK interest spawning stock biomass indicators evaluated in 2015. Indicator values below 1 show spawning stock biomass levels below those capable of producing maximum sustainable yield.

Stock description

Stock code

Indicator

Biomass sustainability

Nephrops in Division VIIa (Irish Sea East. FU 14)

nep-14

5.2

Sustainably Fished

Haddock in Division VIIa (Irish Sea)

had-iris

3.875

Sustainably Fished

Haddock in Divisions VIIb.c.e-k

had-7b-k

3.823

Sustainably Fished

Plaice in Divisions VIIf,g

ple-celt

3.385

Sustainably Fished

Nephrops in the Firth of Clyde + Sound of Jura (FU 13)

nep-13

3.138

Sustainably Fished

Nephrops in Division VIa (North Minch. FU 11)

nep-11

2.676

Sustainably Fished

Whiting in ICES Division VIIb. c. e-k

whg-7e-k

2.383

Sustainably Fished

Nephrops in Division VIa (South Minch. FU 12)

nep-12

1.959

Sustainably Fished

Herring in the Celtic Sea and South of Ireland

her-irls

1.877

Sustainably Fished

Megrim in Division VIb

meg-rock

1.783

Sustainably Fished

Haddock in Division VIb (Rockall)

had-rock

1.722

Sustainably Fished

Herring in Division VIIa North of 52° 30N (Irish Sea)

her-nirs

1.394

Sustainably Fished

Sole in Division VIIe (Western Channel)

sol-echw

1.371

Sustainably Fished

Nephrops in Division VIIa (Irish Sea West. FU 15)

nep-15

1.333

Sustainably Fished

Roundnose grenadier (Coryphaenoides rupestris) in Subareas VI and VII, and Divisons Vb and XIIb

rng-5b67

1.16

Sustainably Fished

White anglerfish in Divisions VIIb,k, and VIIIa, b, d

anp-78ab

1.159

Sustainably Fished

Sole in Divisions VIIf. g (Celtic Sea)

sol-celt

1.131

Sustainably Fished

Megrim in Divisions VIIb,k and VIIIa, b, d

mgw-78

1.123

Sustainably Fished

Plaice Subarea IV (North Sea)

ple-nsea

3.282

Sustainably Fished

Nephrops in Division IVb (Firth of Forth. FU 8)

nep-8

2.274

Sustainably Fished

Plaice in Division VIId (Eastern Channel)

ple-eche

2.106

Sustainably Fished

Saithe in Subarea IV (North Sea) Division IIIa West (Skagerrak) and Subarea VI (West of Scotland and Rockall)

sai-3a46

1.662

Sustainably Fished

Sole in Subarea IV (North Sea)

sol-nsea

1.328

Sustainably Fished

Nephrops in Division IVa (Moray Firth. FU 9)

nep-9

1.324

Sustainably Fished

Herring in Subarea IV and Divisions IIIa and VIId (North Sea autumn spawners)

her-47d3

1.202

Sustainably Fished

Haddock in Subarea IV and Divisions IIIa West and VIa (North Sea. Skagerrak and West of Scotland)

had-346a

1.106

Sustainably Fished

Anglerfish in Subareas IV and VI and Division IIIa

ang-ivvi

1.053

Sustainably Fished

Herring in Subareas I. II. V and Divisions IVa and XIVa (Norwegian spring-spawning herring)

her-noss

1.053

Sustainably Fished

Whiting Subarea IV (North Sea) and Division VIId (Eastern Channel)

whg-47d

1.02

Sustainably Fished

Hake in Division IIIa. Subareas IV. VI and VII and Divisions VIIIa.b.d (Northern stock)

hke-nrtn

6.814

Sustainably Fished

Blue whiting in Subareas I-IX. XII and XIV (Combined stock)

whb-comb

1.908

Sustainably Fished

Mackerel in the Northeast Atlantic (combined Southern. Western and North Sea spawning components)

mac-nea

1.629

Sustainably Fished

Ling in Subareas VI-IX, XII, and XIV, and in Divisions IIIa and IVa

lin-oth

1.523

Sustainably Fished

Black-bellied anglerfish in Divisions VIIb,k and VIIIa,b,d

anb-78ab

0.872

SSB < MSY Btrigger

Herring (Clupea harengus) in Divisions VIa and VIIb.c (West of Scotland. West of Ireland)

her-67bc

0.61

SSB < MSY Btrigger

Whiting in Division VIIa

whg-iris

0.594

SSB < MSY Btrigger

Cod (Gadus morhua) in Divisions VIIe-k (Western English Channel and Southern Celtic Seas)

cod-7e-k

0.57

SSB < MSY Btrigger

Cod (Gadus morhua) in Division VIIa (Irish Sea)

cod-iris

0.496

SSB < MSY Btrigger

Sole in Division VIIa (Irish Sea)

sol-iris

0.382

SSB < MSY Btrigger

Whiting in Division VIa (West of Scotland)

whg-scow

0.225

SSB < MSY Btrigger

Cod (Gadus morhua) in Division VIa (West of Scotland)

cod-scow

0.13

SSB < MSY Btrigger

Plaice in Division VIIe (Western Channel)

ple-echw

0.001

SSB < MSY Btrigger

Sole in Division VIId (Eastern Channel)

sol-eche

0.987

SSB < MSY Btrigger

Cod (Gadus morhua) in Subarea IV and Divisions VIId and IIIa West (North Sea. Eastern English Channel. Skagerrak)

cod-347d

0.931

SSB < MSY Btrigger

Nephrops in Division IVa (Fladen Ground. FU 7)

nep-7

0.928

SSB < MSY Btrigger

Nephrops in Division IVb (Farn Deeps. FU 6)

nep-6

0.659

SSB < MSY Btrigger

Sprat in Subarea IV (North Sea)

spr-nsea

0.346

SSB < MSY Btrigger

Horse mackerel (Trachurus trachurus) in Divisions IIa. IVa. Vb. VIa. VIIa-c. e-k. VIII (Western stock)

hom-west

0.852

SSB < MSY Btrigger

Nephrops in Division VIIb.c.j.k (Porcupine Bank. FU 16)

nep-16

 

Unknown

Plaice in Division VIIa (Irish Sea)

ple-iris

 

Unknown

Spurdog in the Northeast Atlantic

dgs-nea

 

Unknown

Nephrops in Divisions IVb and IVc Botney Gut/Silver Pit (FU5)

nep-5

 

Unknown

North Sea Megrim in Divisions IVa and Via

meg-4a6a

 

Unknown

Whiting in Division VIb (Rockall)

whg-rock

 

Unknown

Cod in VIb Rockall Plateau

cod-rock

 

Unknown

Pollack (Pollachius pollachius) in Subareas VI-VII (Celtic Seas and the English Channel)

pol-celt

 

Unknown

Sprat in Subarea VI and Divisions VIIa-c and f-k (Celtic Sea and West of Scotland)

spr-celt

 

Unknown

 

Table 4: Marine fish (quota) stocks of UK interest spawning stock biomass indicators evaluated in 2016 based on preliminary data. Indicator values below 1 show spawning stock biomass levels below those capable of producing maximum sustainable yield.

Stock description

Stock code

Indicator

Biomass sustainability

Nephrops in Division VIIa (Irish Sea East. FU 14)

nep-14

5.56

Sustainably Fished

Haddock in Division VIIa (Irish Sea)

had-iris

4.885

Sustainably Fished

Nephrops in the Firth of Clyde + Sound of Jura (FU 13)

nep-13

3.355

Sustainably Fished

Plaice in Divisions VIIf,g

ple-celt

3.285

Sustainably Fished

Nephrops in Division VIa (North Minch. FU 11)

nep-11

2.633

Sustainably Fished

Haddock in Divisions VIIb.c.e-k

had-7b-k

2.608

Sustainably Fished

Haddock in Division VIb (Rockall)

had-rock

2.314

Sustainably Fished

Nephrops in Division VIa (South Minch. FU 12)

nep-12

2.076

Sustainably Fished

Whiting in ICES Division VIIb. c. e-k

whg-7e-k

1.826

Sustainably Fished

Megrim in Division VIb

meg-rock

1.688

Sustainably Fished

Nephrops in Division VIIa (Irish Sea West. FU 15)

nep-15

1.667

Sustainably Fished

Herring in the Celtic Sea and South of Ireland

her-irls

1.573

Sustainably Fished

Herring in Division VIIa North of 52° 30N (Irish Sea)

her-nirs

1.393

Sustainably Fished

Sole in Division VIIe (Western Channel)

sol-echw

1.39

Sustainably Fished

Megrim in Divisions VIIb,k and VIIIa, b, d

mgw-78

1.145

Sustainably Fished

White anglerfish in Divisions VIIb,k, and VIIIa, b, d

anp-78ab

1.123

Sustainably Fished

Sole in Divisions VIIf. g (Celtic Sea)

sol-celt

1.081

Sustainably Fished

Cod (Gadus morhua) in Subarea IV and Divisions VIId and IIIa West (North Sea. Eastern English Channel. Skagerrak)

cod-347d

16.364

Sustainably Fished

Plaice Subarea IV (North Sea)

ple-nsea

4.112

Sustainably Fished

Nephrops in Division IVb (Firth of Forth. FU 8)

nep-8

2.729

Sustainably Fished

Plaice in Division VIId (Eastern Channel)

ple-eche

2.46

Sustainably Fished

Saithe in Subarea IV (North Sea) Division IIIa West (Skagerrak) and Subarea VI (West of Scotland and Rockall)

sai-3a46

1.845

Sustainably Fished

Sole in Subarea IV (North Sea)

sol-nsea

1.738

Sustainably Fished

Nephrops in Division IVa (Fladen Ground. FU 7)

nep-7

1.608

Sustainably Fished

Herring in Subarea IV and Divisions IIIa and VIId (North Sea autumn spawners)

her-47d3

1.339

Sustainably Fished

Anglerfish in Subareas IV and VI and Division IIIa

ang-ivvi

1.112

Sustainably Fished

Whiting Subarea IV (North Sea) and Division VIId (Eastern Channel)

whg-47d

1.103

Sustainably Fished

Herring in Subareas I. II. V and Divisions IVa and XIVa (Norwegian spring-spawning herring)

her-noss

1.005

Sustainably Fished

Hake in Division IIIa. Subareas IV. VI and VII and Divisions VIIIa.b.d (Northern stock)

hke-nrtn

7.326

Sustainably Fished

Blue whiting in Subareas I-IX. XII and XIV (Combined stock)

whb-comb

2.236

Sustainably Fished

Mackerel in the Northeast Atlantic (combined Southern. Western and North Sea spawning components)

mac-nea

1.529

Sustainably Fished

Ling in Subareas VI-IX, XII, and XIV, and in Divisions IIIa and IVa

lin-oth

1.522

Sustainably Fished

Black-bellied anglerfish in Divisions VIIb,k and VIIIa,b,d

anb-78ab

0.857

SSB < MSY Btrigger

Cod (Gadus morhua) in Divisions VIIe-k (Western English Channel and Southern Celtic Seas)

cod-7e-k

0.78

SSB < MSY Btrigger

Whiting in Division VIIa

whg-iris

0.603

SSB < MSY Btrigger

Cod (Gadus morhua) in Division VIIa (Irish Sea)

cod-iris

0.527

SSB < MSY Btrigger

Herring (Clupea harengus) in Divisions VIa and VIIb.c (West of Scotland. West of Ireland)

her-67bc

0.522

SSB < MSY Btrigger

Sole in Division VIIa (Irish Sea)

sol-iris

0.413

SSB < MSY Btrigger

Whiting in Division VIa (West of Scotland)

whg-scow

0.364

SSB < MSY Btrigger

Cod (Gadus morhua) in Division VIa (West of Scotland)

cod-scow

0.122

SSB < MSY Btrigger

Sole in Division VIId (Eastern Channel)

sol-eche

0.885

SSB < MSY Btrigger

Haddock in Subarea IV and Divisions IIIa West and VIa (North Sea. Skagerrak and West of Scotland)

had-346a

0.814

SSB < MSY Btrigger

Nephrops in Division IVb (Farn Deeps. FU 6)

nep-6

0.812

SSB < MSY Btrigger

Sprat in Subarea IV (North Sea)

spr-nsea

0.453

SSB < MSY Btrigger

Horse mackerel (Trachurus trachurus) in Divisions IIa. IVa. Vb. VIa. VIIa-c. e-k. VIII (Western stock)

hom-west

0.767

SSB < MSY Btrigger

Nephrops in Division VIIb.c.j.k (Porcupine Bank. FU 16)

nep-16

 

Unknown

Spurdog in the Northeast Atlantic

dgs-nea

 

Unknown

Plaice in Division VIIa (Irish Sea)

ple-iris

 

Unknown

Plaice in Division VIIe (Western Channel)

ple-7e

 

Unknown

Roundnose grenadier (Coryphaenoides rupestris) in Subareas VI and VII, and Divisons Vb and XIIb

rng-5b67

 

Unknown

Nephrops in Division IVa (Moray Firth. FU 9)

nep-9

 

Unknown

Nephrops in Divisions IVb and IVc Botney Gut/Silver Pit (FU5)

nep-5

 

Unknown

North Sea Megrim in Divisions IVa and Via

meg-4a6a

 

Unknown

Whiting in Division VIb (Rockall)

whg-rock

 

Unknown

Cod in VIb Rockall Plateau

cod-rock

 

Unknown

Pollack (Pollachius pollachius) in Subareas VI-VII (Celtic Seas and the English Channel)

pol-celt

 

Unknown

Sprat in Subarea VI and Divisions VIIa-c and f-k (Celtic Sea and West of Scotland)

spr-celt

 

Unknown

Species that are present in the area, but not of commercial importance to UK fisheries (including many elasmobranch stocks) were excluded from this assessment. These stocks are more appropriately considered within the indicators developed for the Marine Strategy Framework Directive on Biological Diversity Descriptor. Historically herring fishing in the Clyde area was important nationally, but there is no current assessment, and uncertainty in the stock identity and its distinctness from herring in the wider and adjacent regions. Therefore, a separate ‘unknown’ entry for Clyde herring has not been made in the indicator. Cod in the north-east Arctic sustains an important level of landings by UK trawlers (approximately 12,000 tonnes in 2015), but given that this is only 1% of the international landings by fisheries targeting the stock and also that the stock is not within European Union waters it was not included in the indicator assessment (the stock is in good status with spawning stock biomass > MSY Btrigger).

Conclusions

The UK Marine Strategy Framework Directive target for reproductive capacity of stock (HM Government, 2015) is that:

  • The reproductive capacity of the stock shall be maintained at, or above levels that will support the long-term exploitation of stocks at FMSY, as indicated by spawning stock biomass of all stocks being above Maximum Sustainable Yield Btrigger.

Since 2012, an average of 59% of marine fish stocks (including Nephrops) with international quota have been exploited sustainably at full reproductive capacity, with spawning stock biomass greater than or equal to MSY Btrigger, and on average 25% of stocks have been over-exploited (spawning stock biomass less than MSY Btrigger). The remaining proportion of marine fish stocks and all national shellfish stocks are currently unknown relative to maximum sustainable yield reference points.

Fisheries management measures have likely contributed to the increase in the proportion of marine fish stocks within safe biological limits. While progress has been made, further improvements are required and are expected given the current implementation of the landing obligation.

Further information

A great proportion of international landings are taken from fish stocks that are in a healthy state (> 90% since 2009) indicating that fisheries are generally targeting healthy marine fish stocks. The indicator assessment demonstrates progression toward Good Environmental Status of UK waters.

Knowledge gaps

Spawning stock biomass estimates for 21% of marine fish stocks remained of unknown status with respect to the level capable of producing Maximum Sustainable Yield in 2016 due to a lack of spawning stock biomass and reference point estimates required to evaluate the performance of the maximum sustainable yield management strategy. All national shellfish stocks were ‘unknown’ relative to reference points. This proportion will continue to decline as information becomes available and assessment methods improve. For some shellfish stocks, current data collection methods are insufficient to support assessments of spawning stock biomass with respect to MSY Btrigger. However, scallop stock assessments, in particular, are improving rapidly (ICES 2015).

Further information

Stock assessments are limited by current data collection, and without expansion of monitoring, some stocks (particularly shellfish) may remain of unknown status.

Some stock units cover a large spatial area, and migrations of fish between national waters occur. Assessments of national waters are related to those of countries. The proportion of each stock that is attributable to national waters is unclear given seasonal and temporal changes in spatial distributions of stocks. The relative impact of differing countries management measures on shared stocks is similarly unclear.

Any changes in the productivity of marine ecosystems, linked to changes in prevailing environmental conditions, will likely impact on the population growth rates of stocks and thus the spawning stock biomass obtainable when exploited at maximum sustainable yield. In light of such changes, MSY Btrigger targets may require an adjustment in future.

Current maximum sustainable yield targets do not explicitly include multi-species interactions between predators and prey. As predator populations increase, prey species may decrease, and further work is required to improve stock level targets (MSY Btrigger) to incorporate information on such interactions.

References

Cefas (2015a) ‘Lobster (Homarus gammarus) Stock Status Report 2014 24 September 2015 (viewed on 23 November 2018)

Cefas (2015b) ‘Edible crab (Cancer pagurus) Stock Status Report 2014 24 September 2015 (viewed on 23 November 2018)

Dobby H, Millar S, Blackadder L, Turriff J, McLay A (2012) ‘Scottish Scallop Stocks: Results of 2011 Stock Assessments Scottish Marine and Freshwater Science Volume 3 No 10. Marine Scotland Science (viewed on 23 November 2018)

European Commission (2013) ‘Regulation (EU) No 1380/2013 of the European Parliament and of the Council of 11 December 2013 on the Common Fisheries Policy (CFP), amending Council Regulations (EC) No 1954/20003 and (EC) No 1224/2009 and repealing Council Regulations (EC) No 2371/2002 Official Journal of the European Union 354, 22-61 (viewed on 22 November 2018)

European Commission (2008) ‘Directive 2008/56/EC of the European Parliament and of the Council of 17 June 2008 establishing a framework for community action in the field of marine environmental policy (Marine Strategy Framework Directive; MSFD) European Parliament and Council of the European Union Official Journal of the European Union 164, 19-40 (viewed on 21 September 2018)

HM Government (2012) ‘Marine Strategy Part One: UK Initial Assessment and Good Environmental Status’ (viewed on 5 July 2018)

HM Government (2015) ‘Marine Strategy Part Three: UK Programme of Measures’ (viewed on 5 July 2018)

ICES (2012) ‘ICES Implementation of Advice for Data-limited Stocks in 2012 in its 2012 Advice ICES CM 2012/ACOM:68, 42 pages (viewed on 22 November 2018)

ICES (2013) ‘Report of the Workshop to Finalize the ICES Data-limited Stock (DLS) Methodologies Documentation in an Operational Form for the 2013 Advice Season and to make Recommendations on Target Categories for Data-limited Stocks (WKLIFE II), 20–22 November 2012, Copenhagen, Denmark ICES CM 2012/ACOM:79, 46 pages (viewed on 22 November 2018)

ICES (2015) ‘Report of the Scallop Assessment Working Group (WGScallop), 6-10 October 2014, Nantes, France ICES CM 2014\ACOM:24, 35 pages (viewed on 22 November 2018)

ICES (2016) ‘Report of the Scallop Assessment Working Group (WGScallop) ICES CM 2015/ACOM:23, 40 pages (viewed on 23 November 2018)

ICES (2016a) ‘General context of ICES advice ICES Advice 2016, Book 1, Section 1.2 pages 1-15 (viewed on 22 November 2018)

ICES (2016b) ‘Report of the Workshop to consider FMSY ranges for stocks in ICES categories 1 and 2 in Western Waters (WKMSYREF4), 13–16 October 2015, Brest, France ICES CM 2015/ACOM:58, 187 pages (viewed on 22 November 2018)

ICES (2016c) ‘Report of the Workshop to consider MSY proxies for stocks in ICES category 3 and 4 stocks in Western Waters (WKProxy), 3–6 November 2015, ICES Headquarters, Copenhagen ICES CM 2015/ACOM:61, 183 pages (viewed on 22 November 2018)

Lassen H, Kelly C and Sissenwine M (2014) ‘ICES advisory framework 1977-2012: from Fmax to precautionary approach and beyond’ ICES Journal of Marine Science 71: 166–172 (viewed on 23 November 2018)

Mesquita C, Dobby H, McLay A (2016) ‘Crab and Lobster Fisheries in Scotland: Results of Stock Assessments 2009 – 2012 Scottish Marine and Freshwater Science Volume 7 No 9. Marine Scotland Science (viewed on 22 November 2018)

Acknowledgements

Assessment metadata
Assessment TypeUK MSFD Indicator Assessment
 

D3.2

Reproductive capacity of commercially exploited stocks of UK interest

 

 
 
Point of contact emailmarinestrategy@defra.gov.uk
Metadata dateWednesday, August 7, 2019
TitleReproductive capacity of commercially exploited stocks of UK interest
Resource abstract

This indicator measures progress towards the objective that populations of all commercially exploited fish and shellfish are within safe biological limits, exhibiting a population age and size distribution that is indicative of a healthy stock

Linkage

This dataset summarises stock assessment advice for quota fish stocks and national shellfish stocks. These files contain data quantifying annual recruitment, biomass, stock size, landings, catches, discards, industrial bycatch, fishing pressure (fishing pressure mean, ranges, and estimated pressure accountable to landings, discards and bycatch) and stock indicators (Flim fisheries mortality that if exceeded would result in the stock falling below Blim, Blim spawning stock Biomass at the limit reference point, Fpa level of catches that if exceeded would result in the stock falling below Bpa, Bpa spawning stock Biomass in relation to the precautionary approach, Fpa, FMSY Maximum sustainable yield, BMSY Maximum sustainable yield biomass trigger) for various fish stocks (fish species in given ICES regions).

Conditions applying to access and use

© Crown 2018 copyright Defra, licenced under the Open Government Licence (OGL).

Assessment Lineage

These data are used to determine the indicator D3.1

Commercial fishing pressure for stocks of UK interest and D3.2 Reproductive capacity of commercially exploited stocks of UK interest. Data processing is carried out by landmark on the CEFMAT interface, as per an r script created collaboratively between Christopher Lynam, Zachary Radford and Joseph Ribeiro (Cefas).

Dataset metadata

This indicator summarises stock assessment advice for quota fish stocks and national shellfish stocks. The input data for quota fish stocks arise from the ICES stock assessment database http://standardgraphs.ices.dk/stockList.aspx, while the data for national shellfish stocks arise from Marine Scotland and Cefas assessments (see links in References).

The UK_ICES_fish_stock_and_shellfish_stock_assessment_data_2017.csv is modified from the ICES stock assessment database. Appended to this is the UK national shellfish stocks data, which were taken from assessment reports provided by Cefas and Marine Scotland. In the dataset, the first column “ICES” identifies those stocks that originate from the ICES stock assessment database with the entry “Y”.

The SPiCT_Stock data2_281117.csv contains ICES stock assessment model outputs. SPiCT refers to 'Stochastic Production model in Continuous Time', the model used to produce outputs for data limited stocks. These data were not released online by ICES when this data were collated (12/09/2017), but instead downloaded directly by www.stockassessment.org (Casper Berg, DTU-Aqua) to Cefas on 08 June 2016.

The SPiCT_Stock data2_281117.csv contains ICES stock assessment model outputs. SPiCT refers to 'Stochastic Production model in Continuous Time', the model used to produce outputs for data limited stocks. These data were not released online by ICES when this data were collated (12/09/2017), but instead downloaded directly by www.stockassessment.org (Casper Berg, DTU-Aqua) to Cefas on 08 June 2016.

Links to datasets identifiers

Please, see doi below

Dataset DOI

https://doi.org/10.14466/CefasDataHub.74

The Metadata are “data about the content, quality, condition, and other characteristics of data” (FGDC Content Standard for Digital Geospatial Metadata Workbook, Ver 2.0, May 1, 2000).

Metadata definitions

Assessment Lineage - description of data sets and method used to obtain the results of the assessment

Dataset – The datasets included in the assessment should be accessible, and reflect the exact copies or versions of the data used in the assessment. This means that if extracts from existing data were modified, filtered, or otherwise altered, then the modified data should be separately accessible, and described by metadata (acknowledging the originators of the raw data).

Dataset metadata – information on the data sources and characteristics of data sets used in the assessment (MEDIN and INSPIRE compliance).

Digital Object Identifier (DOI) – a persistent identifier to provide a link to a dataset (or other resource) on digital networks. Please note that persistent identifiers can be created/minted, even if a dataset is not directly available online.

Indicator assessment metadata – data and information about the content, quality, condition, and other characteristics of an indicator assessment.

MEDIN discovery metadata - a list of standardized information that accompanies a marine dataset and allows other people to find out what the dataset contains, where it was collected and how they can get hold of it.

Recommended reference for this indicator assessment

Lynam, C.P.1, Radford, Z.1, Ribeiro, J.1, Engelhard, G.1, Firmin, C1, Dobby, H.2, Mesquita, C.2, Bluemel, J.1, Bell, E.1, & O'Brien, C.1 2018. Reproductive capacity of commercially exploited stocks of UK interest. UK Marine Online Assessment Tool, available at: https://moat.cefas.co.uk/pressures-from-human-activities/commercial-fish-and-shellfish/reproductive-capacity/

1Centre for Environment, Fisheries and Aquaculture Science

2Marine Scotland