1. Flow, Fish and Fishing: Building Spatial Fishing Scenarios Dave Siegel, James Watson, Chris Costello, Crow White, Satoshi Mitarai, Dan Kaffine, Will White, Bruce Kendall, Steve Gaines UC Santa Barbara

2. What is F3? Flow – how are fish populations connected? –Resource Connectivity Fish – heterogeneity of stock growth & recruitment –Dynamic Externality and Spatial Heterogeneity Fishing – spatial harvesting, economic objectives, distributional impacts over time –Economic Optimality

3. Focus on Larval Connectivity

4. Flow Fish Settlement Habitat Recruitment Harvest Regulation Fishermen Market INFO Climate Flow Fish Settlement Recruitment Flow Fish Settlement Habitat Recruitment Harvest Regulation Fishermen INFO

5. The F3 Approach Circulation & Larval Transport – time / space scales of larval transport & their settlement Stock / Harvest Dynamics – implications of uncertainty on fish stocks, yields & profits Fleet Dynamics – How do fishermen choose when, where & how to fish? Value of Information – How does amount & quality of data available inform the management process?

6. Constructing Fishery Scenarios Build fishing scenarios for SoCal Bight Goal: optimal spatial management of a stock given complete information Pieces –Domain –Stock demographics –Connectivity –Harvest strategy Optimizing it is hard – see the next talk…

7. Southern California Bight

8. 48 patches

9. Stock / Harvest Modeling Next generation stocks = survivors - harvest + new recruits SURVIVORS are surviving adults from previous time HARVEST are those extracted from the fishery NEW RECRUITS are a function of fecundity of the survivors, larval dispersal & mortality, settlement & recruitment to adult stages

10. Stock = Kelp Bass Adults are nearly sedentary –Mature at 3 years Settlement, recruitment & survivability –Multi-year analysis of larval settlement & survey observations by W. White & J. Caselle [in review] –Intra-cohort density dependence on recruitment with a positive association with kelp density –Annual adult survival = f(adult density) Larval connectivity via passive dispersal –Settlement window = 26 to 36 days –Spawning season = May-September –Larvae are found near the sea surface

11. Kelp Cover Distribution Multiyear Kelp Cover from Cal F&G % cover for each patch

12. Lagrangian Particle Trajectories Velocity fields from Oey et al. [2003] data assimilation product Quality good where/when there are data available

13. Connectivity Matrix Source Patches (j) Destination Patches (i) Self Settlement Line Hydrodynamic Connectivity only!!! Catalina Island

14. Role of Larval Life History PLD = 18 dPLD = 72 d PLD alters connectivity (no one pattern holds) Shorter PLD’s show more self-settlement Source Patches (j) Destination Patches (i)

15. Interannual Variation in Connectivity 19941998 Source Patches (j) Destination Patches (i) Hydrodynamic connectivity differs year by year in both strength and location

16. Let’s make some scenarios… Focus on long term assessment of fishing yields –Use long-time mean connectivity & kelp distributions Assume a fishing policy Let TAC = c [Stock] where value of c achieves maximum yield Spatial allocation by ideal free distribution Assumes complete knowledge of system

17. Highest biomass corresponds to kelp density via recruitment success – though not always San Miguel Is Pt Sal Naples Biomass Distribution

18. San Miguel Is Spatial Harvest Yield

19. Hydrodynamic vs. Realized Connectivity Realized connectivity couples hydrodynamics, larval production & habitat factors Source Patches (j) Destination Patches (i) Flow OnlyIncludes Production & Habitat

20. Impose Spatial Closures Close 20% sites semi-randomly

21. Spatial Harvest Yield Yield scenarios can be used for impact assessments Close 20% sites semi-randomly

22. Regional Abundance Regional Yield Harvest Fraction 20% locations closed no closures 20% locations closed no closures

23. Regional Abundance Regional Yield Harvest Fraction Black – no closures Red – previous case Green – 20 random closures

24. Conclusions Constructed fishing scenarios for SoCal Bight Link hydrodynamics & fish biology with management Couples to the Ocean Observatory Initiative Modest spatial closures with management outside often lead to increased fishery yields Heterogeneity in connectivity & demographics leads to increased productivity & yields Not optimal economic sol’n See Chris Costello’s talk next…

25. Flow, Fish & Fishing Webpage www.icess.ucsb.edu/~satoshi/f3

26. Lagrangian Particle Trajectories Velocity fields from Oey et al. [2003] data assimilation product Quality good where/when there are data available

27. Biomass Distribution