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KELP-SEA URCHIN-FISHERMEN DYNAMICS: IMPLICATIONS FOR SMALL-SCALE FISHERIES MANAGEMENT. Nicolas Gutierrez SAFS - UW R Hilborn, AE Punt, LW Botsford, D Armstrong, D Beauchamp. Thesis Sections. I. A spatially-explicit individual-based model of sea urchin, kelp and fishermen
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KELP-SEA URCHIN-FISHERMEN DYNAMICS: IMPLICATIONS FOR SMALL-SCALE FISHERIES MANAGEMENT Nicolas Gutierrez SAFS - UW R Hilborn, AE Punt, LW Botsford, D Armstrong, D Beauchamp
Thesis Sections • I. A spatially-explicit individual-based model of sea urchin, kelp and fishermen • Alternative approaches for sea urchin stock assessment • - Gutiérrez et al. Developing a Bayesian stock assessment framework and decision analysis for the red sea urchin fishery in Baja California, Mexico (Submitted N. Am. J. Fish. Manag.) • III. Exploring dedicated access management strategies for sedentary small-scale fisheries • -Fishing for uni: potential benefits of cooperative harvesting
Fishing for uni: potential benefits of cooperative harvesting • Background & Motivation • Roe fishery, with marked spatio-temporal patterns in gonad quality/yield (depending on food availability) • SDWA and the fishing industry concerned about sustainability and economic viability. Optimize harvest flexibility and quality by: • - getting biological information to better manage the fishery (BE program) • - developing a community-based management strategy • Fishing for uni: Selective harvesting of “well fed urchins”, by fishing those areas where the gonad yield is at its peak
Recruits Fishing for uni: potential benefits of cooperative harvesting • Approach • 5 areas with same number of urchins (B0 = 20,000) • Competitive fishery: each diver go to the area that produced the best return (as total uni production: Y = gonad yield x abundance) • Cooperative managed fishery: each diver is directed to fish each area at/around its seasonal peak • Constant recruitment (legal/mature): • Seasonal/pulse recruitment:
Area 3 Fishing for uni: potential benefits of cooperative harvesting DATA: Spatio-temporal variations in gonad yield (%) a b
Catch (lbs) Revenue (US$) Constant recruitment Seasonal recruitment Competitive Cooperative Competitive Cooperative Competitive Cooperative Fishing for uni: potential benefits of cooperative harvesting Preliminary results
Fishing for uni: potential benefits of cooperative harvesting • Next steps • Increase spatial resolution of data set on gonad yield, abundance, etc • Density-dependence recruitment • Market considerations (e.g. price depending on catches 2 weeks earlier) • Gonad Quality threshold (e.g. > 5.2 % ~ 0.75 $ per lbs) • Depletion levels (e.g. B=0.4•B0) • Include processing costs for “bad” urchins