1. From verge of collapse to ecosystem-based fisheries management
Rainer Froese
RD3 Seminar
GEOMAR, Kiel,

2. Overview Overview of fisheries-related research
The reformed Common Fisheries Policy
The MSY concept
New approaches to estimate MSY
Safe biological limits
Size matters
Questions

3. Overview of fisheries-related research

4. Fisheries-relevant Research in Recent Years See www. fishbase
Fisheries-relevant Research in Recent Years See for PDFs
Martell, S. and R. Froese, A simple method for estimating MSY from catch and resilience. Fish and Fisheries 14: , doi: /j x
Froese, R. and M. Quaas Rio+20 and the reform of the Common Fisheries Policy in Europe. Marine Policy 39:53-55, doi.org/ /j.marpol
Villasante, S., D. Gascuel and R. Froese Rebuilding fish stocks and changing fisheries management, a major challenge for the Common Fisheries Policy reform in Europe. Ocean and Coastal Management 70:1-3,
Froese, R. and M. Quaas Mismanagement of the North Sea cod by the European Council. Ocean and Coastal Management 70:54-58, doi: /j.ocecoaman
Quaas, M., R. Froese, H. Herwartz, T. Requate, J.O. Schmidt and R. Voss Fishing industry borrows from natural capital at high shadow interest rates. Ecological Economics, doi: /j.ecolecon
Froese, R. and A. Proelss Is a stock overfished if it is depleted by overfishing? A response to the rebuttal of Agnew et al. to Froese and Proelss “Evaluation and legal assessment of certified seafood”. Marine Policy 38: , doi: /j.marpol
Froese, R. and A. Proelss Evaluation and legal assessment of certified seafood. Marine Policy 36: , doi: /j.marpol
Froese, R., D. Zeller, K. Kleisner and D. Pauly What catch data can tell us about the status of global fisheries. Marine Biology 159: , doi: /s

5. More
Kleisner, K., D. Zeller, R. Froese and D. Pauly Using global catch data for inferences on the world's marine fisheries. Fish and Fisheries doi: /j x
Norse, E.A., S. Brooke, W.W.L. Cheung, M.R. Clark, I. Ekeland, R. Froese, K.M. Gjerde, R.L. Haedrich, S.S. Heppell, T.Morato, L.E. Morgan, D. Pauly, R. Sumaila and R. Watson Sustainability of deep-sea fisheries. Marine Policy 36: ,
Pauly, D. and R. Froese Comments on FAO's State of Fisheries and Aquaculture, or 'SOFIA 2010'. Marine Policy 36:
Froese, R. and M. Quaas Three options for rebuilding the cod stock in the eastern Baltic Sea. Marine Ecology Progress Series 434:
Froese, R Fishery reform slips through the net. Nature 475:7
Froese, R., T.A. Branch, A. Proelß, M. Quaas, K. Sainsbury and C. Zimmermann Generic harvest control rules for European fisheries. Fish and Fisheries 12:
Khalilian, S., R. Froese, A. Proelss, T. Requate Designed for Failure: A Critique of the Common Fisheries Policy of the European Union. Marine Policy 34:
Froese, R. and A. Proelß Rebuilding fish stocks no later than 2015: will Europe meet the deadline? Fish and Fisheries 11: ,
Froese, R The continuous smooth hockey stick: a newly proposed spawner-recruitment model. Journal of Applied Ichthyology 24: ,
Froese, R., A. Stern-Pirlot, H. Winker and D. Gascuel Size Matters: How Single-Species Management Can Contribute To Ecosystem-based Fisheries Management. Fisheries Research 92:
Froese, R Keep it simple: three indicators to deal with overfishing. Fish and Fisheries 5:86-91

6. The Reformed Common Fisheries Policy

7. The new CFP
Article 2.2
The CFP shall apply the precautionary approach to fisheries management, and shall aim to ensure that exploitation of living marine biological resources restores and maintains populations of harvested species above levels which can produce the maximum sustainable yield.

8. CFP and the Ecosystem Approach
Preamble of CFP
Whereas: ...
(11) The CFP should contribute to the protection of the marine environment, to the sustainable management of all commercially exploited species, and in particular to the achievement of good environmental status by 2020, as set out in Article 1(1) of Directive 2008/56/EC of the European Parliament and of the Council1.
(13) An ecosystem-based approach to fisheries management needs to be implemented, environmental impacts of fishing activities should be limited and unwanted catches should be avoided and reduced as far as possible.

9. CFP and the Ecosystem Approach
Article 4.1 (9) 'ecosystem-based approach to fisheries management' means an integrated approach to managing fisheries within ecologically meaningful boundaries which seeks to manage the use of natural resources, taking account of fishing and other human activities, while preserving both the biological wealth and the biological processes necessary to safeguard the composition, structure and functioning of the habitats of the ecosystem affected, by taking into account the knowledge and uncertainties regarding biotic, abiotic and human components of ecosystems; Article 4.1 (11) 'low impact fishing' means utilising selective fishing techniques which have a low detrimental impact on marine ecosystems or which may result in low fuel emissions, or both;

10. CFP and Protected Areas
Preamble of CFP
(22) In order to contribute to the conservation of living aquatic resources and marine ecosystems, the Union should endeavour to protect areas that are biologically sensitive, by designating them as protected areas. In such areas, it should be possible to restrict or to prohibit fishing activities. When deciding which areas to designate, particular attention should be paid to those in which there is clear evidence of heavy concentrations of fish below minimum conservation reference size and of spawning grounds, and to areas which are deemed to be bio-geographically sensitive. Account should also be taken of existing conservation areas. [....]

11. Article 8, Establishment of fish stock recovery areas 1
Article 8, Establishment of fish stock recovery areas 1. The Union shall, while taking due account of existing conservation areas, endeavour to establish protected areas due to their biological sensitivity, including areas where there is clear evidence of heavy concentrations of fish below minimum conservation reference size and of spawning grounds. In such areas fishing activities may be restricted or prohibited in order to contribute to the conservation of living aquatic resources and marine ecosystems.

12. CFP and Minimizing Impact of Fishing
Article 2.3 The CFP shall implement the ecosystem-based approach to fisheries management so as to ensure that negative impacts of fishing activities on the marine ecosystem are minimised, and shall endeavour to ensure that aquaculture and fisheries activities avoid the degradation of the marine environment.

13. Article 4.1 (17) 'minimum conservation reference size' means the size of a living marine aquatic species taking into account maturity, as established by Union law, below which restrictions or incentives apply that aim to avoid capture through fishing activity; such size replaces, where relevant, the minimum landing size;

14. The MSY concept

15. MSY, Bmsy and Fmsy MSY is the maximum sustainable yield
Biomass (B) is the weight of the fish in the sea
Bmsy is the biomass that can produce MSY
Fmsy is the fishing pressure that eventually results in Bmsy and MSY
A stock is and remains in good status if B > Bmsy and F < Fmsy

16. Background of the MSY Concept
Schaefer 1954; BioDivPopGrowthMSY.xls

17. Surplus Production Implications
Surplus production (Y) is the production of biomass beyond what is needed to maintain current population size
If a fishery only catches the surplus production, then the population size remains
If a fishery catches more, then the population shrinks
If it catches less, then the population grows

18. Surplus Production Implications
Surplus production has a maximum at about half of unexploited population size B∞
Keeping a population at 0.5 B∞ allows catching MSY forever
A population is kept stable if the fishing rate F equals the intrinsic growth rate rt
MSY is reached at ½ B∞ and ½ rmax
Thus, MSY is reached at Fmsy = ½ rmax

19. New Approaches to Estimate MSY

20. MSY from Catch and Resilience
For a population to sustain a history of output such as catch, it needs to have had a certain size and productivity
If you know the time series of annual production (biomass taken out for human use), and you know the productivity of the species, then you can calculate biomass and reference points

21. Catch-MSY Method Martell & Froese 2013
Output of the Catch-MSY method showing “viable” pairs surplus production rate r and
unexploited biomass k for North Sea cod. The red line indicates all r-k pairs that would result in
the same estimate of MSY; the red circle indicates the geometric. While the estimate of MSY is
robust, the geometric mean r = 0.24 depends on the lower bound for r.

22. New CMSY-Method in prep.
Same approach as in Catch-MSY
New, objective approach to determine rmax
This results in surprisingly good estimates of biomass time series, Bmsy and Fmsy
Formal Bayesian approach under development

23. Herring in the Gulf of Riga I
1) assumed r-k space
3) < 1% outliers in k
2) rmax in upper half
4) minimize SE of MSY
4-step zoom-in on area used to estimate geometric mean r, k and MSY

24. Herring in the Gulf of Riga II
Fisheries reference points MSY (bold red line in upper left graph), Fmsy = 0.5 r and Bmsy = 0.5 k

25. Herring in the Gulf of Riga III
Blue lines are prior biomass windows, medium resilience is prior for r. Red line is observed
Biomass, black line predicted biomass, with 5th and 95th percentile. Required data are catch.

26. Herring in the Gulf of Riga IV
Catch/biomass ratio u as proxy for F. Dotted line is umsy. Black line is predicted, red line
is observed.

27. Herring in the Central Baltic
Better fit possible by replacing defaults with “informative priors”.

28. North Sea Herring

29. Safe biological limits

30. The Past Common Fisheries Policy (until 2013)
Apply a precautionary approach to fishing
Keep fish stocks within safe biological limits

31. Safe Biological Limits
Conceptual drawing of the hockey stick relationship between spawning stock size and recruitment. SSBlim marks the border below which recruitment declines, SSBpa marks a precautionary distance to SSBlim, and
2 * SSBpa can be used as a proxy for SSBmsy, the stock size that can produce the maximum sustainable catch.
(Froese et al. submitted)

32. Status of European Stocks
Extending the trends
in the last 3 years for the
95% confidence limits…
SSBpa
UNCLOS
UNFSA
Based on the ICES Stock Summary database 10/2013 with data for 45 stocks. Update of Froese & Proelss 2010

33. Quality of Scientific Advice
Fisheries science holds that mortality caused by sustainable fishing (Fmsy) should be less than natural mortality (M) caused by e.g. predation, diseases, natural hazards or old age
Doubling mortality reduces life time and reproductive phase by half and also reduces average size and fecundity
However, in 29 of 38 stocks (76%) with available data, the ICES estimate of Fmsy exceeded M, on average by 62%
(Froese et al. submitted)

34. Fishing Mortality may be Higher
True F/Fmsy may be higher because
of unrealistically high Fmsy
in 76% of the stocks
Based on the ICES Stock Summary database 10/2013 with data for 45 stocks
(Froese et al. submitted)

35. Quality of Scientific Advice
ICES provides estimates of the border of safe biological limits (SSBpa). Below SSBpa recruitment may be reduced and the stock is at increased risk of collapse
In 14 of 43 stocks (33%) with available data, the ICES estimate of SSBpa fell below the median estimate of three independent scientific methods.

36. Hake Southern Stock
Froese et al. submitted

37. Underestimation of Safe Biological Limits
SSBpa
ICES three independent methods
Analysis of stock-recruitment data for North Sea Doggerbank Sandeel (san-ns1), with three different methods. [S-R_HS_5_san-ns1.r]
(Froese et al. submitted)

38. Stock Biomass may be Lower
True SSB/SSBpa may be lower because of unrealistically low SSBpa
in 33% of the stocks
Based on the ICES Stock Summary database 10/2013 with data for 45 stocks
(Froese et al. submitted)

39. Common Sense Rules for Ecosystem-based Management
Only catch fish for direct human consumption
Only catch species with high resilience
Do not damage the ecosystem
Take less than nature
Let fish grow and spawn before capture

40. Size Matters (Froese et al. 2008, Froese et al. in prep)
Three important points in the life of species with indeterminate growth:
Length at maturity (Lm90)
Length Lmax dW/dt where growth is maximum
Length Lopt where cohort biomass is maximum

41. Natural Selection “Economizes” Organisation of ReproductionIf
reproduction happens when production of tissue is maximum
Lm <= Lmax dW/dt (= in semelparous, < in iteroparous)
Lm <= Lopt (then topt = generation time)
Lmax dW/dt = Lopt (then most offspring are produced when production of tissue is maximum)

42. Basic Equations
𝑁 𝑡 = 𝑁 0 𝑒 −𝑀 𝑡

43. Economizing Reproduction
Life history strategies for the timing of reproduction: A) semelparous, B) iteroparous with
parental care, C) broadcast spawners. Note: Blue line is not to scale.
Froese and Pauly 2013

44. Tradeoff between generation time and peak fecundity
Froese et al. in prep.

45. Timing of spawning
Based on 232 studies Froese and Pauly 2013

46. Size Matters! Ll
Lm90
Biomasse of a cohort (e.g. cod) vs length. Maturity is reached at Lm90 = 59 cm. Maximum
growth and high fecundity is reached at Lopt = 86 cm. However, legal fishing starts at Ll = 35 cm.
Froese et al. 2008

47. Fishing with Fmsy starting at Ll will not rebuild the stocks
Lm90
Cohort biomasse (e.g. cod) without fishing (bold curve) and with F = Fmsy fishing
Starting at legal length (dotted curve) Froese et al. 2008

48. Fishing with F=M starting at Lcopt rebuilds the stock
Large biomass (~ 1.2 Bmsy)
Higher catch
Lower cost
Lm90
Unexploited cohort biomass (bold curve), with Fmsy –fishing (dotted curve), and with
F=M fishing starting at Lcopt (dashed curve), so that the mean length in the catch and
In the exploited part of the stock equals Lopt Froese et al. in prep.

49. Impact of Fishing on Size Structure
Length-frequency without fishing (bold curve), with F = Fmsy fishing after Ll , and with F = M
Fishing after Lcopt. With Lcopt fishing all fish reach maturity and about 2/3 reach Lopt. With
Fmsy fishing after Ll , only 2/3 reach maturity and only 1/3 reach Lopt Froese et al. in prep.

50. Thank You