Descriptor 3 for determining Good Environmental Status (GES) under the MSFD was defined as...
Transcript of Descriptor 3 for determining Good Environmental Status (GES) under the MSFD was defined as...
MARINE STRATEGY FRAMEWORK DIRECTIVE
GOOD ENVIRONMENTAL STATUS (GES) ON DESCRIPTOR 3
Descriptor 3 for determining Good Environmental Status (GES) under the MSFD was
defined as “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”Directive 2008/56/EC, Annex I
In the Commission Decision 2010/477/EU three criteria including methodological
standards were described for this descriptor. methodological standards are defined methods developed and agreed in the framework of
European or international conventions Criterion 3.1 Level of pressure of the fishing
activity • Primary indicator: Indicator 3.1.1 Fishing
mortality (F) • Secondary indicator (if analytical assessments
yielding values for F are not available): Indicator 3.1.2 Ratio between catch and
biomass index (hereinafter ‘catch/biomass ratio’) Criterion 3.2 Reproductive capacity of the stock • Primary indicator: Indicator 3.2.1 Spawning Stock
Biomass (SSB) • Secondary indicator (if analytical assessments
yielding values for SSB are not available): Indicator 3.2.2 Biomass indices
Descriptor 3
Criterion 3.3 Population age and size distribution • Primary indicator: Indicator 3.3.1 Proportion of
fish larger than the mean size of first sexual maturation • Primary indicator: Indicator 3.3.2 Mean maximum
length across all species found in research vessel surveys • Primary indicator: Indicator 3.3.3 95% percentile
of the fish length distribution observed in research vessel surveys • Secondary indicator: Indicator 3.3.4 Size at first
sexual maturation
Following the MSFD in that “Each Member State shouldtherefore develop a marine strategy for its marine waters which, while being specificto its own waters, reflects the overall perspective of the marine region or subregion
concerned.”
Descriptor 3: 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.
Catch/Biomass ratio
Biomass indices
Size at first maturation
3. 1 Fishing pressure
F
Ref level: FMSY
3. 2 Reproductive
capacity
SSB
Ref level: SSBMSY
3. 3 Population age and
size distribution
95% percentileof length distribution
Prop of fish > mean size offirst sexual maturation
Mean maximum length across species
Criterion
Primary indicator
Secondary indicator
Selection of commercially exploited (shell)fish populations
Stocks for which primary indicators and reference levels are available
Species for which no reference levels are available
Interpretation of GES
Assessment of current status in relation to GES
Roadmap to the GES assessment process
ApproachTheoretical concepts, criteria, methodologies for: Selection of commercial species Stocks with analytical assessments Species/stocks with info from monitoring programmes
Case Studies:
Bay of Biscay/IberiaBaltic Sea Celtic SeasNorth Sea Mediterranean
Synthesis: Different interpretations of GES
Assessment of current status against GES
30°E20°E10°E0°10°W20°W
50°N
40°N
30°N
20°N
Baltic Sea
Greater North Sea, incl. the Kattegat and the English Channel
Celtic Seas
Bay of Biscay and the Iberian Coast
Macaronesia
North-east Atlantic Ocean
Mediterranean Sea
Western Mediterranean Sea
Adriatic Sea
Ionian Sea and the Central Mediterranean Sea
Aegian-Levantine Sea
Regional Seas around Europe
Black Sea
Iceland Sea
Norwegian Sea
Barents Sea
Black Sea
Quality of informationStock Status
Robust quantitative assessment
Preliminary quantitative assessment
Estimates of fishing mortality / exploitation (F) from catch curves (age / length data)
Trends in catch-per-unit-effort (CPUE)
Uncertaintyincreases
Data-limited / model-poor
%Analytical 38Trends based 10Trends, survey only 39
Catch only 13
Dr Carl O’Brien2012
Reduced quality and utility of advice for management
Descriptor 3
The data available are inadequate to: estimate the current population size; and the catch resulting from fishing at a desired F.
Advice on catches only? ICES’ MSY approach calls for a
determination of the status of exploitation relative to FMSY and considerations of the stock trend.
MSY ? – the maximum average long-term catch that may be taken from a fish stock under prevailing environmental conditions
Without a radical change in approach … implies that approximately 60% of the 188 (158) stocks will have no useful scientific advice w.r.t. MSY
Issues that ICES has not satisfactorily dealt with:
Data-limited / model-poor stocks
What is FMSY?What is the current stock
exploitation?How should we manage future
exploitation?
Indeces
Categorisation of stocks into one of seven basis types:
1) Data rich stocks (quantitative assessments)2) Negligible landings stocks3) Stocks with analytical assessments that are treated
qualitatively4) Stocks for which survey indices (or unbiased CPUE)
indicate trends5) Stocks for which reliable catch data are available for
short time-series6) Truly data-poor stocks (landings only)7) Stocks caught in minor amounts as by-catch
Category 7 – stocks that are part of stock complexes and are primarily caught as by-catch species in other targeted fisheries. The development of indicators may be most appropriate for such stocks; e.g. NS brill in the targeted NS plaice and sole fishery.
Trends/Ref points
Trends/Ref points
relative management advice on the direction and relative scale of the changes required to achieve targets.
Category 4: Stocks for which survey indices (or unbiased CPUE) indicate trends
Requirements: the time series that should be used to determine the
status of the stock and provide catch advice. Category 5: Stocks for which reliable catch data
are available for short time-series - Under consideration(further assessments)
Category 3:Stocks with analytical assessments that are treated qualitatively
Requirements:
What are the prospects for the future? On-going studies;
What is FMSY? life history characteristics include, among other
things, longevity, fecundity and recruitment variability
What is the current stock exploitation? Harvest ratio proxies and survey (DCF / FSP)
catch curves How should we manage future exploitation?
simple trend-based rules (survey / catch)