from verge of collapse to ecosystem-based fisheries management rainer froese rd3 seminar geomar,...

From verge of collapse to

ecosystem-based fisheries management

Rainer FroeseRD3 Seminar

GEOMAR, Kiel, 15.05.2014

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

Overview of fisheries-related research

Fisheries-relevant Research in Recent YearsSee www.fishbase.de/rfroese for PDFs

• Martell, S. and R. Froese, 2013. A simple method for estimating MSY from catch and resilience. Fish and Fisheries 14: 504-514, doi:10.1111/j.1467-2979.2012.00485.x

• Froese, R. and M. Quaas. 2013. Rio+20 and the reform of the Common Fisheries Policy in Europe. Marine Policy 39:53-55, doi.org/10.1016/j.marpol.2012.10.007

• Villasante, S., D. Gascuel and R. Froese. 2012. 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. 2012. Mismanagement of the North Sea cod by the European Council. Ocean and Coastal Management 70:54-58, doi:10.1016/j.ocecoaman.2012.04.005

• Quaas, M., R. Froese, H. Herwartz, T. Requate, J.O. Schmidt and R. Voss. 2012. Fishing industry borrows from natural capital at high shadow interest rates. Ecological Economics, doi:10.1016/j.ecolecon.2012.08.002

• Froese, R. and A. Proelss. 2012. 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 38:548-550, doi:10.1016/j.marpol.2012.07.001

• Froese, R. and A. Proelss. 2012. Evaluation and legal assessment of certified seafood. Marine Policy 36:1284-1289, doi:10.1016/j.marpol.2012.03.017

• Froese, R., D. Zeller, K. Kleisner and D. Pauly. 2012. What catch data can tell us about the status of global fisheries. Marine Biology 159: 1283-1292, doi:10.1007/s00227-012-1909-6

More• Kleisner, K., D. Zeller, R. Froese and D. Pauly. 2012. Using global catch data for inferences on the

world's marine fisheries. Fish and Fisheries doi: 10.1111/j.1467-2979.2012.00469.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. 2012. Sustainability of deep-sea fisheries. Marine Policy 36:307-320,

• Pauly, D. and R. Froese. 2012. Comments on FAO's State of Fisheries and Aquaculture, or 'SOFIA 2010'. Marine Policy 36:746-752.

• Froese, R. and M. Quaas. 2011. Three options for rebuilding the cod stock in the eastern Baltic Sea. Marine Ecology Progress Series 434:197-2011

• Froese, R. 2011. Fishery reform slips through the net. Nature 475:7• Froese, R., T.A. Branch, A. Proelß, M. Quaas, K. Sainsbury and C. Zimmermann. 2011. Generic harvest

control rules for European fisheries. Fish and Fisheries 12:340-351• Khalilian, S., R. Froese, A. Proelss, T. Requate. 2010. Designed for Failure: A Critique of the Common

Fisheries Policy of the European Union. Marine Policy 34:1178-1182• Froese, R. and A. Proelß. 2010. Rebuilding fish stocks no later than 2015: will Europe meet the

deadline? Fish and Fisheries 11:194-202, • Froese, R. 2008. The continuous smooth hockey stick: a newly proposed spawner-recruitment model.

Journal of Applied Ichthyology 24: 703-704, • Froese, R., A. Stern-Pirlot, H. Winker and D. Gascuel. 2008. Size Matters: How Single-Species

Management Can Contribute To Ecosystem-based Fisheries Management. Fisheries Research 92:231-241

• Froese, R. 2004. Keep it simple: three indicators to deal with overfishing. Fish and Fisheries 5:86-91

The Reformed Common Fisheries Policy

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.

CFP and the Ecosystem ApproachPreamble of CFPWhereas: ...• (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.

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;

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. [....]

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.

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.

• 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;

The MSY concept

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

Background of the MSY Concept

Schaefer 1954; BioDivPopGrowthMSY.xls

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

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

New Approaches to Estimate MSY

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

Catch-MSY MethodMartell & 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.

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

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Herring in the Gulf of Riga I

4-step zoom-in on area used to estimate geometric mean r, k and MSY

1) assumed r-k space

2) rmax in upper half

3) < 1% outliers in k

4) minimize SE of MSY

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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

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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.

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Catch/biomass ratio u as proxy for F. Dotted line is umsy. Black line is predicted, red lineis observed.

Herring in the Gulf of Riga IV

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Herring in the Central Baltic

Better fit possible by replacing defaults with “informative priors”.

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North Sea Herring

Safe biological limits

The Past Common Fisheries Policy(until 2013)

• Apply a precautionary approach to fishing• Keep fish stocks within safe biological limits

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)

Status of European Stocks

Based on the ICES Stock Summary database 10/2013 with data for 45 stocks. Update of Froese & Proelss 2010

Extending the trends in the last 3 years for the 95% confidence limits…

SSBpa

UNCLOS UNFSA

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)

Fishing Mortality may be Higher

Based on the ICES Stock Summary database 10/2013 with data for 45 stocks

True F/Fmsy may be higher because of unrealistically high Fmsy in 76% of the stocks

(Froese et al. submitted)

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.

Hake Southern Stock

Froese et al. submitted

Underestimation of Safe Biological Limits

Analysis of stock-recruitment data for North Sea Doggerbank Sandeel (san-ns1), with three different methods. [S-R_HS_5_san-ns1.r]

SSBpa ICES three independent methods

(Froese et al. submitted)

Stock Biomass may be Lower

Based on the ICES Stock Summary database 10/2013 with data for 45 stocks

True SSB/SSBpa may be lower because of unrealistically low SSBpa in 33% of the stocks

(Froese et al. submitted)

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

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

Natural Selection “Economizes” Organisation of Reproduction

If• reproduction happens when production of

tissue is maximum• Lm90 <= Lmax dW/dt (= in semelparous, < in iteroparous)

• Lm90 <= Lopt (then topt = generation time)

• Lmax dW/dt = Lopt (then most offspring are produced when

production of tissue is maximum)

Basic Equations

𝑑𝑊 𝑑𝑡ൗ� = 3 𝐾 𝑊∞ ቀ൫1− 𝑒−𝐾ሺ𝑡−𝑡0ሻ൯2 −൫1− 𝑒−𝐾ሺ𝑡−𝑡0ሻ൯3ቁ

𝑊𝑡 = 𝑊∞ (1− 𝑒−𝐾ሺ𝑡−𝑡0ሻ)𝑏

𝑁𝑡=𝑁0𝑒−𝑀 𝑡

𝐿𝑜𝑝𝑡 = 𝐿∞ 33+ 𝑀𝐾

𝐿𝑐_𝑜𝑝𝑡 = 𝐿∞ 𝐾(3𝐹+ 2𝑀)(𝐹+ 𝑀)(3𝐾+ 𝑀)

𝑌 𝑅ൗ�= 𝐹 𝑊∞ 𝑒−𝑀ሺ𝑡𝑐−𝑡𝑟ሻቊ 1𝑀+ 𝐹− 3 𝑒−𝐾 𝑟1𝑀+ 𝐹+ 𝐾+ 3 𝑒−2𝐾 𝑟1𝑀+ 𝐹+ 2𝐾− 𝑒−3𝐾 𝑟1𝑀+ 𝐹+ 3𝐾ቋ

𝐵 𝑅ൗ�= 𝑊∞ە۔

ۓ 1− 𝑒−𝑀 𝑟2𝑀 + 𝑒−𝑀 𝑟2𝐹+ 𝑀− 3𝑒−𝐾 𝑟3 ቈ1− 𝑒−ሺ𝑀+𝐾ሻ𝑟2𝑀+ 𝐾 + 𝑒−ሺ𝑀+𝐾ሻ𝑟2𝐹+ 𝑀+ 𝐾 +

+3𝑒−2𝐾 𝑟3 ቈ1− 𝑒−ሺ𝑀+2𝐾ሻ𝑟2𝑀+ 2𝐾 + 𝑒−ሺ𝑀+2𝐾ሻ𝑟2𝐹+ 𝑀+ 2𝐾 − 𝑒−3𝐾 𝑟3 ቈ1− 𝑒−ሺ𝑀+3𝐾ሻ𝑟2𝑀+ 3𝐾 + 𝑒−ሺ𝑀+3𝐾ሻ𝑟2𝐹+ 𝑀+ 3𝐾

Economizing Reproduction

Froese and Pauly 2013

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.

Tradeoff between generation time and peak fecundity

Froese et al. in prep.

Timing of spawning

Based on 232 studies. Froese and Pauly 2013

Size Matters!

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

Lm90Ll

Fishing with Fmsy starting at Ll will not rebuild the stocks

Cohort biomasse (e.g. cod) without fishing (bold curve) and with F = Fmsy fishing Starting at legal length (dotted curve). Froese et al. 2008

Lm90

Fishing with F=M starting at Lcopt

rebuilds the stock

Unexploited cohort biomass (bold curve), with Fmsy –fishing (dotted curve), and withF=M fishing starting at Lcopt (dashed curve), so that the mean length in the catch andIn the exploited part of the stock equals Lopt. Froese et al. in prep.

Lm90- Large biomass (~ 1.2 Bmsy)- Higher catch- Lower cost

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. WithFmsy fishing after Ll , only 2/3 reach maturity and only 1/3 reach Lopt. Froese et al. in prep.

Thank You