1. Fishery indicators V.Raykov,IO-BAS
Descriptor 3
Fishery indicators V.Raykov,IO-BAS
Five main steps were identified to assess Good Environmental Status GES for D3:
• Selection of commercially exploited (shell)fish populations relevant to the
MSFD (sub)region, or MS-specific sub-division, being assessed with respect
to D3;
• Identification of stocks that can be assessed in relation to the primary assessment
criteria for D3.1 and D3.2;
• Determination of criteria to apply to stocks that can not be assessed in relation
to the primary assessment criteria, and identification of stocks that
can be assessed according to these secondary criteria;
• Interpretation of how to define GES for D3 with respect to combining individual
stock assessments at the criteria level, and how to combine criteria
level assessments at the descriptor level;
• Assessment of current status in relation to GES.

2. The Choice (1) Identification of the appropriate area
; (2) Match of existing spatial units to that area;
(3) Choice of data
source;
(4) Choice of time period;
(5) Selection criteria.

3. Assessment (1) all indicators with
reference levels, (2) not all reference levels, or (3) no reference levels.
For commercial populations that do not have full assessments scientific monitoring
surveys were identified as a potential data source for calculating some secondary indicators.
Three options for determining the current status from trend-based time series
were considered: (1) comparing the recent period mean with the long-term average
(2) comparing the current value of the indicator in relation to the historic mean
setting a threshold based on appropriate percentile of the Normal distribution; (3) detection
of trends.

4. GES
GES Interpretation 1: strict interpretation of the Commission Decision
where MSY reference levels are treated as a limit and thus all stocks must
meet the MSY requirement
• GES Interpretation 2: the MSY reference levels are considered as a target
and thus half the stocks must achieve the MSY requirement, and all stocks
must achieve precautionary reference levels
• GES Interpretation 3: the MSY reference levels are considered as a target
and stocks need to achieve this requirement on average. This average is
calculated accounting for the ‘distance’ individual stocks are above or below
the MSY reference level.

5. For the overall assessment of Descriptor 3, three approaches were considered in the case studies: (1) no aggregation across criteria; (2) application of the one-out-all-out aggregation rule or “assessment by worst case”; or (3) application of weights for the different criteria.
A higher proportion of assessed stocks increases the quality of the GES assessment;
species/taxa for which no information is available decreases the quality;
length of the time-series (with/without Reference levels);

6. Stocks for which analytical stock assessments are conducted
F, SSB
the populations
for which only information from monitoring programs is available.
Proportion of fish larger than the mean size of first sexual maturation
‘catch/biomass ratio’;
Mean maximum length across all species found in research vessel surveys
Biomass indices
95% percentile of the fish length distribution observed in research vessel surveys
Size at first sexual maturation, which
may reflect the extent of undesirable genetic effects of exploitation

7. Issues to be considered
Appropriate areas – divisions/subdivisions?
The time period over which the landings data are considered determines the relative importance of species or species groups;
Threshold for inclusion of species – 1% but in Baltic Sea 0.5% as a threshold for salmon – important but with low catches;

8. Member States shall, when implementing their obligations under this Directive, take due
account of the fact that marine waters covered by their sovereignty or jurisdiction form an integral
part of the following marine regions:
(a) the Baltic Sea;
(b) the North-east Atlantic Ocean;
(c) the Mediterranean Sea;
(d) the Black Sea.

10. Fishing mortality

11. Fmsy,Fmax,F0.1
Based on single species analysis (without ecosystem considerations; Predator-prey relationship);

12. SSB – single stock estimatins

13. Species covered by monitoring programs

14. What is GES?

17. Indicators calculation

18. Black Sea Indicator calculations for BG waters
Видове
2006
2007
2008
2009
2010
2011
Mean catch %
Трицона (Sprattus sprattus)
48.54
Рапани (Rapanа spp.)
43.40
Сафрид (Trachurus mediterraneus )
62.83
115.89
179.92
176.91
165.27
394.84
182.61
2.36
Барбуня (Mullus barbatus )
6.11
12.60
16.64
48.19
72.40
176.20
55.36
0.72
Сем. Попчета (Gobiidae)
31.34
73.89
25.66
36.82
44.24
85.18
49.52
0.64
Морска лисица (Raja clavata)
3.56
25.58
46.81
72.21
93.43
48.32
0.52
Калкан (Scophtalmus maximus)
14.81
66.89
54.87
52.47
46.45
38.06
45.59
0.59
Черноморска бодлива акула (Squalus acanthias)
6.23
23.98
22.75
9.46
77.16
81.01
36.76
0.48
Хамсия (Engraulis encrasicholus )
6.46
60.44
28.03
42.41
64.73
18.11
36.70
0.47
Карагьоз, дунавска скумрия (Alosa immaculata)
17.72
25.81
27.48
37.38
59.08
51.80
36.54
Лефер (Pomatomus saltatrix)
8.46
8.22
25.18
52.54
63.49
29.39
31.21
0.40
other
47.52
145.48
78.51
126.27
148.58
102.82
115.86
1.40
Общо

19. Biomass from scientific surveys

20. Catch, Fishing mortality
Daskalov et al., 2012

21. Catch and biomass - TACs

22. Catch/Biomass ratio

23. Trends

24. Lmax (mean values) across all species caught in surveys

25. 95% Percentile from L

26. Sprat and turbot
Lmean Reference level for the given period of “healthy stock” condition
Holt (1958), Lopt – which assure max Y/R if all specimen were caught at the Lopt.
Froese et al. (2008) - Yield of the individuals reached Lopt, won’t affect negatively age structure of the population;
Froese and Sampang (2012) – the stock will have proportion of older individuals,if the mean length in the catch is within the interval : Lopt +/- 10%, i.e Lopt < Lmean < 1.1 Lopt.
For Lopt calculation the following equations is used:
logLopt = * logL∞ (Froese and Binohlan, 2000).
where: L∞ - asymtotic lenght, Lopt – length at max Y/R

27. Classification of the state of Sprat population according to Lmean
7.20 cm < Lmean < 8.80 cm.

28. Long-term Lmean

29. Cumulative distribution of Length groups by years
Cumulative contribution of TL=7cm varied %(max 2008,min 2010)

30. Age distribution

31. Turbot example (Black Sea)

32. Lmean Long term

33. Cumulative distribution of lenght

34. Thank you for the attention!