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Building FLR

Building FLR. A open source framework for bio-economic modelling, to allow alternative assumptions about stock and fleet dynamics to be considered when evaluating alternative management strategies Open Source and the need to collaborate

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Building FLR

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  1. Building FLR • A open source framework for bio-economic modelling, to allow alternative assumptions about stock and fleet dynamics to be considered when evaluating alternative management strategies • Open Source and the need to collaborate • "I think the real issue about adoption of open source is that nobody can really ever ‘design’ a complex system. That's simply not how things work: people aren't that smart - nobody is. And what open source allows is to not actually "design" things, but let them evolve, through lots of different pressures in the market, and having the end result just continually improve” • Linus Torvalds • http://www.flr-project.org/doku.php

  2. Changing Policy Needs • Changing policy needs require a move from short-term reactive management to long-term strategic planning e.g. • The Common Fisheries Policy (CFP) requires long-term management and recovery plans that take into account • Conservation status of stocks • Their biological characteristics • Characteristics of the fisheries in which the stocks are caught • Economic impact of the measures on the fisheries concerned • World Summit on Sustainable Development (WSSD) requires targets • Recovery of stocks to MSY by 2015 Ecosystem Based Approach to Fisheries Management(EBFM) requires • Progressive implementation of an ecosystem-based approach

  3. Precautionary Approach • Requires management advice to comprehensively take into account uncertainties and associated risks due to • Natural variability • Model mis-specification: fish don’t know the theory of VPA • Estimation Error: Even if they did, doesn’t mean we’d get a good fit • Imperfect information • Imperfect implementation

  4. Traditional Advice “Traditional” fisheries management is based upon setting annually a total allowable catch (TAC). Which relies upon a “best” assessment, conditioned on assumptions about stock and fleet dynamics, given the most recent available data. For example when looking at recovery plans the most recent assessment is used to project forward for different management options e.g. i) reducing effort, and hence fishing mortality, ii) changing mortality on younger fish by changing mesh size in selected fisheries or iii) temporal spatial closures.

  5. Projections Assessment and management advice is often present as estimates of SSB, yield, F and recruitment, e.g. where the 2006 ICES North Sea cod assessment is projected to 2016 with an F equivalent to the 2006 level. The black lines represent the expected historic estimates and the expected outcomes, with two additional lines representing the upper 75th and the lower 25th percentile. The expected values and estimates of uncertainty are generated from Monte Carlo simulations In reality the stock will not equal the expected values rather it will be one of the individuals trajectories

  6. Validation of “Traditional Advice” Before making a projection to evaluate management options it makes sense to check how well you can predict. Therefore an assessment was performed on the data that would have been available in 2001. The assessment was then projected for five years to evaluate how well stock assessment working group methods can predict the outcome of the proposed management measure. This projection was done for a the actual reported This was then compared with the most recent assessment Even though catches and recruitment are the same the current assessment of spawning stock biomass (red) is very different from what we predicted. While fishing mortality is actually much higher than what we predicted.

  7. Equally plausible hypotheses There is also often a lack of knowledge about stock and fleet dynamics, and inability to control fishery systems. Traditional advice assumes that (i) stock assessment models accurately reflect both population and fisheries dynamics, (ii) input data are appropriate and not biased, and (iii) management measures are perfectly implemented. The ICES North Sea cod assessments estimates the “unallocated removals” required to remove bias in survey trends, However “unallocated removals” could be due to increased natural mortality, discarding or misreported landings. What if the problem is an increase in predation on cod because of an increase in red gurnards?

  8. Evaluation If we can’t predict how can we provide advice? Management Strategy Evaluation (MSE) allows testing of the robustness of management strategies to a lack of knowledge and/or data, the objective is no longer to come up with “the answer” but to ask “What if?” and to choose between alternative management options by comparing their performance. For example in an evaluation of Mediterranean swordfish first a projection for a constant fishing mortality equal to current effort levels was made. A variety of management plans were evaluated to try and recover the stock to BMSY by 2030; red shows the expected outcome for a constant fishing mortality strategy and green for a constant catch strategy.

  9. Management Strategy Evaluation Advice doesn’t depend upon predicting the actual outcome but by comparing the relative performance of alternative actions. This must includes bio-economic factors since if two policies have same biological impact but differing economic impacts, then it is possible to derive a preferred option: FLR http://www.flr-project.org/doku.php

  10. Hypotheses Biological Economic Fleet behaviour Stock/Fleet Dynamics The “Fishery” The “Fishery” The “Fishery” Alternatives Measures Data Management Measures Management Management Strategy Evaluation Not used to set quotas but to work out whether we should be setting quotas at all!

  11. OPERATING MODEL Represents the “true” dynamics of the system against which performance will be measured MANAGEMENT PROCEDURE Assess status of stock and set management options depending upon perceived status of fishery stock(s) MODEL CONDITIONING Management decision stage Fleet dynamics FLFleet Management procedure FLHCR Biological reference points (e.g. MSY) FLBRP Hypotheses IMPLEMENTATION MODEL FLEcon INITIAL CONDITIONS Biological Economic Fleet behaviour Stock/Fleet Dynamics SUMMARY STATISTICS Used to evaluate performance of management procedures against objectives. Population biology Assessment procedure Stock dynamics FLBiol OBSERVATION ERROR MODEL Generation of data on fishery and stocks. FLOEM Perceived stock FLStock Stock assessment (e.g. VPA) FLAssess The “Fishery” The “Fishery” The “Fishery” Alternatives Measures Data Management Measures Stock processes e.g. Recruitment FLSR Auxiliary information (e.g. tuning indices) FLIndices Assessment assumptions Management Management Strategy Evaluation Not used to set quotas but to work out whether we should be setting quotas at all!

  12. Precautionary Approach • Requires management advice to comprehensively take into account uncertainties and associated risks due to • Natural variability • Model mis-specification: fish don’t know the theory of VPA • Estimation Error: Even if they did, doesn’t mean we’d get a good fit • Imperfect information • Imperfect implementation

  13. Generic Management Plans STECF WORKING GROUP ON EVALUATION OF "POLICY STATEMENT" HARVEST RULES. • The European Commission asked the STECF to evaluate HCRs for setting TACs based on ICES stock assessments and forecasts. An main objective of was is to provide stability (i.e. 15% TAC rule) for the industry but the HCRs also had to be evaluate with respect to associated risks for the stocks and the fisheries, in terms of the future development of • “spawning biomass, and associated risks of transgressing biological reference points.” • “yield, and associated risks” The SG was requested to conduct Management Strategy Evaluation (MSE) using an Operating Model/Management Procedure approach • 1) Set target F Fy=max(Fsq,F0.1) 2) Check F limit if Fy > Fpa then set Fy = Fp and stimate TACy 3) Check SSB limit if SSBy+1<Bpa then re-estimate TACy so that SSBy+1 = Bpa 3) Check catch stability if TACy ≤ (1- α)TACy -1 thenTACy = (1- α)TACy-1 else if TACy ≥ (1+ α)TACy-1  thenTACy = (1+ α)TACy-1 4) Check for stock collapse and implement recovery plan If SSBy < Bpa and SSBy+1 <= SSBy then re-estimate TACy so SSBy+1 = SSBy 5) If impossibleclose fishery if SSBy+1 < SSBy even if F=0.0then set F = 0.01. 6) Check for rise in F if Fy > Fsq then set Fy = Fsq and re-estimate TACy

  14. STECF Underline STECF underlines the need to include economic impact evaluations to the analyses. CFP legislation requires this, and economic information may help the stakeholders to find acceptable management options more easily. STECF aggress with SGMOS that a follow up meeting would be valuable but stresses that additional progress and the completion of the TORs is only likely to be achieved if adequate intersessional work is undertaken.

  15. Lessons Learnt Feedback from Industry • A lot to absorb in short time • Beginning of a process • Liked the idea and encouraged it’s use • The collaborative approach is good • Should be an ongoing process • Time horizons – • 10 yrs - vessel mortgage • 3 yr period very interesting • Lack of expertise and workload are limitations

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