Ministry of Food Agriculture and Fisheries Danish Institute

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 flatfisheries 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

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

Ministry of Food, Agriculture and Fisheries Danish Institute for Fisheries Research Case study : the North Sea flatfisheries • 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

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 noneconomic factors – Expected profit or revenue – Tradition – Seasonality – Management – Skipper skills – …

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:

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)

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

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

Ministry of Food, Agriculture and Fisheries Danish Institute for Fisheries Research Simulation 2004 -2017 : Robustness trials Plaice Sole 350000 70000 300000 60000 250000 SSB 50000 200000 40000 150000 30000 100000 20000 50000 10000 0 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 0. 9 0. 8 0. 7 F 0 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 0. 6 0. 5 0. 4 0. 3 0. 2 0. 3 Littleeffectatatthe thestocklevel Little 0. 2 0. 1 0 0 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

Ministry of Food, Agriculture and Fisheries Danish Institute for Fisheries Research Simulation 2004 -2017 : Robustness trials Plaice Sole 350000 70000 300000 60000 250000 SSB 50000 200000 40000 150000 30000 100000 20000 50000 10000 0 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 0. 9 0. 8 0. 7 F 0 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 0. 6 0. 5 0. 4 Flandings 0. 3 0. 2 0. 4 F(landings) 0. 2 F(landings) 0. 1 0 0 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

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

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

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

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

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.