Harvest of Commercially Exploited Fish and Shellfish (EO 3)

Common Indicator 7: Spawning stock Biomass

Geographical scale of the assessment:
Regional, Mediterranean Sea
Contributing countries:
GFCM Contracting and Cooperating Non Contracting Parties
Mid-Term Strategy (MTS) Core Theme:
2-Biodiversity and Ecosystems
Ecological Objective:
E03: Populations of commercially exploited fish and shellfish are within biologically safe limits.
IMAP Common Indicator:
Common Indicator (CI7) Spawning stock Biomass (EO3)
Indicator Assessment Factsheet Code:

GES Definition: Achieving or maintaining good environmental status requires that SSB values are equal to or above SSBMSY, the level capable of producing maximum sustainable yield (MSY).

GES Targets:

  • State: B > Bthr



The indicators of Good Environmental Status of Commercially Exploited fish are quantitative proxies to describe the status of a specific fish stock (i.e. the fish population from which catches are taken in a given fishery) as well as the anthropogenic pressure imposed on it through fishing activities. Those indicators are regularly used in fisheries management to assess the sustainability of fisheries, as well as the performance of management measures (Miethe et al., 2016), by monitoring how far the indicator is from previously agreed targets (i.e. reference points).

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Assessment methods

The complete set of main fishery indicators adopted to assess current status of Mediterranean stocks as well as their temporal trend is reported in the last SAC Report (FAO, 2017). Below are listed the ones, for which a common methodology has been already developed (GFCM, 2017b) and discussed during the meeting of the Correspondence Group on Monitoring (CORMON), Biodiversity and Fisheries (UNEP/MAP, 2017a) as well as the 6th meeting of the Ecosystem Approach Coordination Group (UNEP/MAP, 2017b

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Results and Status, including trends

Analysis of the information at hand from both the GFCM and the STECF, revealed that estimates of biomass (SSB or total) with corresponding proxies for BLIM and BPA were available for 60 stocks in the Mediterranean Sea (Table 2). Of these, 25 (42%) were found to be in a situation of low biomass, 22 (37%) at intermediate biomass and 13 (22%) at high biomass.

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Validated reference points for Spawning Stock Biomass are only available for a few stocks, and therefore the quality assessment included in this report is based on the empirical approach taken by the GFCM Working Groups on Stock Assessment that compares current biomass with the historical series of biomass as estimated from a validated stock assessment or directly from validated surveys at sea. The analysis of 60 different stocks, along the Mediterranean Sea, shows that around 42% show low biomass, 37% were considered to show an intermediate biomass and 22% showed high biomass.

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Key messages

  • Up to 42% of the stocks assessed in the Mediterranean show a low biomass in comparison with the existing time series, and only for 22% of the stocks the biomass is considered to be relatively high in relation to the time series
  • Riparian states have recently explicitly recognized low biomass of key stocks in the Mediterranean as a key challenge in the context of blue growth and food security for coastal communities

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Brooks, E. N., Powers, J. E., & Cortés, E. (2010). Analytical reference points for age-structured models: application to data-poor fisheries. – ICES Journal of Marine Science, 67: 165–175.

Colloca, F., Mastrantonio, G., Jona Lasinio, G., Ligas, A., & Sartor, P. (2014). Parapenaeus longirostris (Lucas, 1846) an early warning indicator species of global warming in the central Mediterranean Sea. J. Mar. Sys., 138:29–39

FAO (1997). Fisheries Management. FAO Technical Guidelines for Responsible Fisheries No. 4. Rome, FAO.

FAO (2016). The State of the Mediterranean and Black Sea Fisheries. General fisheries for the Mediterranean. Rome, Italy. 152pp.

FAO (2017). General Fisheries Commission for the Mediterranean. Report of the nineteenth session of the Scientific Advisory Committee on Fisheries (Ljubljana, Slovenia, 16–19 May 2017) 184 pp.

Fletcher, W.J., Chesson, J., Fisher M., Sainsbury, K.J., Hundloe, T., Smith, A.D.M. & B. Whitworth (2002). National ESD Reporting Framework for Australian Fisheries: The 'How To' Guide for Wild Capture Fisheries. FRDC Project 2000/145, Canberra, Australia. http://www.fisheriesesd.com/c/pubs/index.cfm

Froese, R., Garilao, C., Winker, H., Coro, G., Demirel, N., Tsikliras, A., Dimarchopoulou, D., Scarcella, G., & Sampang-Reyes, A. (2016). Exploitation and Status of European Stocks,  Report about the outcome of four workshops in 2016, about the assessment of all European stocks commissioned by OCEANA, Düsternbrooker Weg.

GFCM (2014a).  Scientific Advisory Committee (SAC) - Subcommittee on Stock Assessment (SCSA), Report of the Working Group on Stock Assessment of Small Pelagic species (WGSASP), Bar, Montenegro (28 January – 1 February 2014), 52pp.

GFCM (2014b). First MedSuit Regional Workshop on indicators and targets to ensure GES of commercially exploited marine populations in the GFCM area. Rome, Italy, 6–7 November 2014. 14pp.

GFCM (2017a). GFCM Data Collection Reference Framework (DCRF). Version: 2017. 115pp.

GFCM (2017b). Good environmental status indicators, GFCM:SAC19/2017/Inf.20

Miethe, T., Dobby, H. & McLay, A. (2016). The Use of Indicators for Shellfish Stocks and Fisheries: A Literature Review. Scottish Mar. and Freshw. Sci., 7: 2043-7722.

Tsikliras, A.C., Dinouli, A., Tsiros, V.Z., & Tsalkou, E. (2015). The Mediterranean and Black Sea Fisheries at Risk from Overexploitation. PLoSONE 10(3): e0121188. https://doi.org/10.1371/journal.pone.0121188.

UNEP/MAP (2012) 17th Ordinary Meeting of the Contracting Parties to the Convention for the Protection of the Marine Environment and the Coastal Region of the Mediterranean and its Protocols, Paris (France), 8-10 February 2012. Initial Integrated Assessment of The Mediterranean Sea: Fulfilling Step 3 of the Ecosystem Approach Process (UNEP(DEPI)/MED IG.20/Inf.8)

UNEP/MAP (2017a). Meeting of the Correspondence Group on Monitoring (CORMON), Biodiversity and Fisheries, Madrid, Spain, 28 February – 1 March 2017. Draft of Common indicator factsheets for Biodiversity (EO1), NIS (EO2) and Fisheries (EO3) (UNEP(DEPI)/MED WG.430/3)

UNEP/MAP (2017B). 6th Meeting of the Ecosystem Approach Coordination Group, Athens, Greece, 11 September 2017. IMAP Common Indicator Guidance Facts Sheets (Biodiversity and Fisheries) (UNEP(DEPI)/MED WG.444/6/Rev.1)


CORMON        Correspondence Group on Monitoring

CWP                Coordinating Working Party on Fishery Statistics

DCRF               Data Collection Reference Framework

E                      Exploitation rate

EAF                  FAO Ecosystem Approach to Fisheries

EBR                 Exploitation Biomass Ratio

EcAp                Ecosystem Approach

F                      Fishing mortality

GES                 Good Environmental Status

GFCM              General Fisheries Commission for the Mediterranean

GSA                 Geographical Sub Areas

IUU                   Illegal, Unreported and Unregulated (fishing estimates)

MSY                 Maximum Sustainable Yield

RFMO              Regional Fisheries Management Organization

SAC                 GFCM Scientific Advisory Committee on Fisheries

SAFs                Stock Assessment Forms

SoMFi              The State of Mediterranean and Black Sea fisheries

SSB                 Spawning Stock Biomass

STECF             European Union Scientific, Technical and Economic Committee for Fisheries

TL                    Total Landing

WGSAs           Working Groups on Stock Assessment


For more information please visit the GFCM website: