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Evaluation of North Sea Haddock Management Strategy: A Case Study

Explore the history, evaluation, results, and future work of the North Sea haddock management plan through stakeholder views, simulations, and assessment frameworks.

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Evaluation of North Sea Haddock Management Strategy: A Case Study

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  1. Jo King: Management strategy evaluation for North Sea haddock using FLR Coby L. Needle (FRS) Fisheries Management Evaluation Frameworks in Action: The EFIMAS Conference Renaissance Hôtel, Brussels, 11-12 March 2008

  2. Outline • Management plan evaluation (MSE) - rationale • North Sea haddock management plans • History of evaluation • The original and revised plans • The results • Conclusions and future work • Stakeholder view (Mike Park, SFF)

  3. Management simulations: rationale • Simulation models: • Framework for evaluation of management strategies • Test many different strategies • Determine risk of adverse outcomes • Avoids “real-world experiments” • Facilitated by FLR tools developed under EFIMAS – COMMIT - FISBOAT

  4. Management simulations: conceptual loop Define starting state Biology Simulate “real” population Growth models Recruitment Knowledge Simulate sampling Uncertainty Simulate assessment Management Simulate management advice Risk analysis Harvest control rules

  5. Management simulations: evaluation loop Start Management proposal Discuss problems with managers and stakeholders and suggest solutions Draw high-level conceptual flowchart of proposal 1 Preliminary analysis Consistent? no yes Draw low-level flowchart of HCR evaluation simulation (including high-level flowchart of proposal) and validate problems? 2 Write pseudo-code and validate problems? no Implement in computer code and test yes 3 Meets objectives? Finish

  6. NS haddock: background • North Sea haddock are managed jointly by the EU and Norway • Plan agreed in 1999 • Came into force in January 2005 • Review carried out during 2006 • Revision agreed in November 2006 • Revised plan implemented January 2007 • Further review during 2007 • Second revision by December 2009

  7. NS haddock: history of evaluation • Several previous attempts at evaluation • Two examples: • EU-Norway Expert Group, June 2004 • ICES Ad hoc Group on Long-Term Advice, April 2005 • Hampered by inadequate software and lack of clarity • Development of FLR increases flexibility • Implementation still difficult

  8. NS haddock: history of evaluation • Evaluation of original plan: • Scottish stakeholder meetings, Aberdeen, April and July 2006 • ICES Methods WG, Galway, June 2006 • ICES WGNSSK, Copenhagen, September 2006 • ICES ACFM, Copenhagen, October 2006 • EU-Norway Consultations, Bergen and Brussels, November 2006 • ICES WK on Limit and Reference Points, Gdynia, January 2007

  9. NS haddock: history of evaluation • Evaluation of revised plan: • ICES Methods WG, Woods Hole, March 2007 • Poster at Haddock 2007 symposium, Portsmouth NH, October 2007 • Paper for Fisheries Research

  10. Original plan: text

  11. Current year = y Assessment to y-1 Year? Risk? Forecast to y+2 Original plan: flowchart yes SSBy+2 < Blim? no ??? “Keep SSB > B(lim)” Set TACy+1 so that mean Fy+1 = 0.3 Ages? “Target F = 0.3” “Unless B < Bpa” SSBy+2 < Bpa after application of Fy+1? “Exploitation pattern” yes ??? no Several holes and cannot be fully evaluated in current form Finish

  12. Revised plan: text

  13. Revised plan: changes • Constraint (± 15%) on interannual quota variation • Specific time to measure biomass • Sliding-F rule (see next slide) • Agreed at EU-Norway November 2007 • But not evaluated • To be reviewed by end 2009

  14. Revised plan: sliding F rule

  15. Revised plan: flowchart

  16. Revised plan evaluation: assumptions • FLR objects used • Some FLR methods also • But some needed rewriting • Growth • Fixed weights-at-age in simulation • Discards • Fixed proportion-at-age • Compliance • Assumed 100% • Recruitment • Assumed one large year-class every ten years

  17. Revised plan evaluation: assumptions Discard assumptions

  18. Revised plan evaluation: assumptions Historical recruitment

  19. Revised plan evaluation: assumptions

  20. Revised plan: results

  21. Revised plan: results

  22. Revised plan: results

  23. Revised plan: results

  24. Revised plan: results

  25. Revised plan: results

  26. Revised plan: results

  27. Revised plan: results

  28. Future work • Banking and borrowing • Improved biological modelling: • Recruitment • Growth • Multispecies & spatial aspects • Improved fisheries modelling: • Discarding • Multifleet & spatial aspects • Sensitivity analyses • Code optimisation

  29. Would a simpler case study be better?

  30. Would a simpler case study be better?

  31. Would a simpler case study be better? • Possible scenario: the “lake” model • One lake • One species • One vessel • Explore management implications • Apply lessons to real-world situations • Long-term project

  32. References

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