1. Ministry of Food, Agriculture and Fisheries Danish Institute for Fisheries Research ICES Symposium on management strategies - SFMS-32 Integrating fishing choices in a bioeconomic simulation model for mixed-fisheries : a case study of the North Sea flatfish fisheries Bo. S. Andersen, Y. Vermard, C. Ulrich,, H. Hovgård, P. Sparre (DIFRES), D. Bromley (CEFAS), S. Mardle (CEMARE), JJ Poos (IMARES), H. von Oostenbrugge (LEI) EU-project TECTAC

2. Ministry of Food, Agriculture and Fisheries Danish Institute for Fisheries Research The TEMAS model Follow-up of FAO BEAM models Generic and modular multispecies - multifleet bioeconomic model for management scenarios. Full feedback Operating Model + Management Procedure Cornerstone :Focus on long-term and short-term fleet dynamics –One fleet can engage in several fisheries –Fleet dynamics based on discrete choice models Open-source VB and user-friendly interface

3. Ministry of Food, Agriculture and Fisheries Danish Institute for Fisheries Research Case study : the North Sea flatfish fisheries Multiple dimensions –2 stocks + other species –3 countries –11 fleets (vessel type) + other fleets –25 fisheries (trip type) + other fisheries One single realistic run with low sole recruitment Scenarios: –Run 1 : TAC + Constant 2003 effort –Run 2 : TAC + effort allocation model –Run 3 : Effect of increased economic attractiveness

4. Ministry of Food, Agriculture and Fisheries Danish Institute for Fisheries Research Effort allocation model. From RUM to TEMAS Fishermen allocate their effort across areas, gears, target species etc. In which order? –Proxy : Fisheries as 1-level independent choices Probability of choice : balance between various economic and non- economic factors –Expected profit or revenue –Tradition –Seasonality –Management –Skipper skills –…–…

5. Ministry of Food, Agriculture and Fisheries Danish Institute for Fisheries Research Effort allocation model. From RUM to TEMAS RUM : Random Utility Model : trip-based analysis of effort allocation TEMAS : Multiple Discrete Choice model : raising RUM empirical results to a fleet-based simulation model: –Simplification of choice model –Implementation of choice variables in TEMAS –Constant parameters –This can be expressed with a general logit model:

6. Ministry of Food, Agriculture and Fisheries Danish Institute for Fisheries Research Effort allocation model for North Sea fleets From individual based choice model to fleet based model: –Simplified utility function : –U (Fl,t.m) = β 1. VPUE (pre month) + α 1 EFFORT% (pre month) + α 2 EFFORT% (pre year) –From trip to month Activated in second year In Run 3: different of weight of economic attractiveness are applied ( β 1 x 5-10-20-40-100 )

7. Ministry of Food, Agriculture and Fisheries Danish Institute for Fisheries Research Danish seine fleet (good fit) Fishery 1 Fishery 2 Fishery 3 Fishery 4 predicted observed Danish Gillnet fleet (moderate fit)

8. Ministry of Food, Agriculture and Fisheries Danish Institute for Fisheries Research Historic period 1998-2003 : validation trials PlaiceSole SSB F landings Discards

9. Ministry of Food, Agriculture and Fisheries Danish Institute for Fisheries Research Simulation 2004 -2017 : Robustness trials PlaiceSole SSB F Little effect at the stock level

10. Ministry of Food, Agriculture and Fisheries Danish Institute for Fisheries Research F (landings) 0 50000 100000 150000 200000 250000 300000 350000 20042005200620072008200920102011201220132014201520162017 0 10000 20000 30000 40000 50000 60000 70000 20042005200620072008200920102011201220132014201520162017 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 20042005200620072008200920102011201220132014201520162017 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 20042005200620072008200920102011201220132014201520162017 Simulation 2004 -2017 : Robustness trials PlaiceSole SSB F Flandings

11. Ministry of Food, Agriculture and Fisheries Danish Institute for Fisheries Research Effect of TAC on landings Plaice landings Sole landings TAC Cum. monthly Landings Fleet: Dutch beam trawl fleet (221-1105 kw)

12. Ministry of Food, Agriculture and Fisheries Danish Institute for Fisheries Research F (partial) % changes in F p TAC vs. BEHAV Influence of effort model at the fleet level

13. Ministry of Food, Agriculture and Fisheries Danish Institute for Fisheries Research Relative effect of increased economic attractiveness - stock FIGURE PlaiceSole SSB F F From 10 to 20

14. Ministry of Food, Agriculture and Fisheries Danish Institute for Fisheries Research Relative effect of increased economic attractiveness - fleet Danish Seine fleet (positive effect) Dutch beam trawl fleet >1105kw (negative effect) Revenue Contribution margin

15. Ministry of Food, Agriculture and Fisheries Danish Institute for Fisheries Research Discussion - conclusions Successful implementation of simple behaviour model into a bioeconomic model for management scenarios. Including behaviour gives a better understanding of linkages in mixed-fisheries systems. Strong effect of single-species TAC on effort allocation. Importance of fleet-based approach, rather than stock-based or fishery-based. Fleets may react differently Parameter estimations : needs sensitivity analysis to fleets and fisheries definition. Difficulty to set dimensions (stocks, fleets, areas…). Case study not responsive enough – fisheries might not be a good enough proxy for fishing choices.