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Mixed fisheries issues for North Sea Cod

Explore technical interactions between cod and haddock in mixed fisheries, implications of varying TAC strategies, and recommendations for consistent TACs across stocks for robust management.

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Mixed fisheries issues for North Sea Cod

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  1. EFIMAS CONFERENCE, 11-12 MARCH 2008, BRUSSELS Mixed fisheries issues for North Sea Cod Clara Ulrich, Katell Hamon, (Stuart Reeves) DTU Aqua. National Institute of Aquatic Resources Danmarks Tekniske Universitet ICES SGMIXMAN, FP6 AFRAME, (FP6 EFIMAS)

  2. Issue : technical interactions cod-haddock Low cod biomass High haddock biomass • Effects of cod recovery plan not as wide as expected • Stocks caught together by main demersal fleets DTU Aqua. National Institute of Aquatic Resources Danmarks Tekniske Universitet

  3. How might TACs work in such situations? • Low cod TAC, taken with low effort / high haddock TAC, taken with a higher level of effort • Fleet dilemna: • stop fishing when cod TAC caught and underutilise haddock TAC (”min effort” scenario) • go on fishing until haddock TAC caught and get overquota catches of cod (”max effort” scenario) • What are the long-term effects of such scenarios? • simulation work, with 11 fleets and ICES/EU management procedures DTU Aqua. National Institute of Aquatic Resources Danmarks Tekniske Universitet

  4. (Hamon et al., 2007) Results Min Effort Max Effort Black : “Real truth” (simulated underlying population) Green : “Perceived truth” (seen from VPA’s eyes and used for deciding upon management) DTU Aqua. National Institute of Aquatic Resources Danmarks Tekniske Universitet

  5. The next step : providing mixed-fisheries advice • Question : which single-species TAC should be proposed to be consistent across stocks? • Methodology : The Fcube approach (ICES MixMan 2006 - 2008) • Main focus : fleets (vessel types) and fisheries (activity types) • Each fleet has its own set of incentives based on its set of quota shares • Hypotheses are proposed on their likely behaviour and level of effort (max, min, valuable species, days at sea regulation…) • corresponding landings (< quota share) and overquota catches (> quota share) are estimated DTU Aqua. National Institute of Aquatic Resources Danmarks Tekniske Universitet

  6. Example : investigating effects of 2007 TACs • Cod, haddock, whiting, saithe, sole, plaice, Nephrops • Very restrictive cod TAC, unrestrictive whiting TAC • All international North Sea fleets (19) • Scenarios : • ”min” (stop fishing when first quota exhausted) • ”max” (stop fishing when last quota exhausted) • ”value” (effort towards most valuable quota shares) • ”status quo” (unchanged effort between 2006 and 2007) • ”DAS reduction” (partial reduction of cod-targeting fisheries) • ”cod” (action necessary to avoid cod overquota for all fleets) DTU Aqua. National Institute of Aquatic Resources Danmarks Tekniske Universitet

  7. Saithe TAC Haddock TAC Plaice TAC Cod TAC Sole TAC ICES SGMixMan, 2008) Results DTU Aqua. National Institute of Aquatic Resources Danmarks Tekniske Universitet

  8. Results DTU Aqua. National Institute of Aquatic Resources Danmarks Tekniske Universitet

  9. Conclusions • Inconsistent 2007 TACs; single-species management objectives cannot be reached simultaneously • At current levels of effort, large over quota catches of cod are estimated to have happened in 2007 • It is possible to test the biological and economic effects of alternative consistent TACs (short-, medium- and long-term), as a basis for robust mixed-fisheries management plans • This approach can be extended to non-target species and broader ecosystem approach DTU Aqua. National Institute of Aquatic Resources Danmarks Tekniske Universitet

  10. Comments from the customer • ICES Study Group on Mixed-fishery Management • EU FP6 Aframe project • STECF Sub-groups • Effort management • Cod recovery • Context • Tool to be used in ICES, annual, short-term advice • Not EFIMAS!

  11. Management advice; TACs and beyond • TAC advice • Based on annual ICES assessments • Implicit assumption, TAC acts to restrict F • i.e. when TAC exhausted, fishing stops • Effort advice • No scientific basis at present • Effects • Direct – if available effort limiting • Indirect – change activity if more effort available there • Other management measures • Indirect; fleets will change behaviour in some way.

  12. Fcube in practice • Two components • Retrospective • Forecast • Original intention • Derive sets of consistent TACs for mixed fisheries • But: • very dependent on assessment quality • Very data demanding • Risk of falling back into the prediction trap. • Recent context • Not just TACs, also effort, closed areas, cod avoidance measures • Increased interest in non-traditional species, e.g. skates and rays

  13. Effort trends by major gear categories Recent Fs (standardised to mean)

  14. Fcube in practice - conclusions • Understanding the past is at least as important as forecasting the future • How has fleet activity changed in response to past management and conditions? • Forecast better used in an indicative, rather than prescriptive, way. • Fcube approach could be effective in a participatory context • The inclusion of information on fleets and their fisheries is essential in the current context • Fleets – link to economics • Fisheries – link to non-target species & other ecosystem components • Fishing activity is linked to fishing mortality

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