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Simulating Larval Dispersal in the Santa Barbara Channel James R. Watson 1, David A. Siegel 1, Satoshi Mitarai 1, Lie-Yauw Oey 2, Changming Dong 3 1 Institute for Computational Earth System Science University of California, Santa Barbara, 2 Atmospheric and Oceanic Science Program, Princeton University, 3 Insitute of Geophysical and Planetary Physics, University of California, Los Angeles This is Important because For any patch I can tell you where those particles that settled in it originated from and for those particles that came from it I can tell you where they went. For example What does this all mean Where to and Where from: Patches Future Directions IMPORTANT I have simulated the dispersal of only water packets that have the potential to have larvae within. For actual larvae I need to add BIOTIC factors - simple demographics. I need to make ensemble runs in order to gain a statistical understanding of random or PERSISTENT larval settlement. Settlement: Within the settlement competency window of Kelp Bass (day 26 to 36) I count which patches particles travel to. This creates a SOURCE DESTINATION relationship. We need to know where fish larvae come from and where fish larvae go. We need to know the mechanism of dispersal. We need to know source and sink locations. Knowing the spatial dynamics of populations will improve nearshore fisheries management and the design of Marine Protected Areas. Patches are defined as sites of POTENTIAL HABITAT for fish stocks. Spawning period: Particles are seeded uniformly throughout these patches. They are released every day for the period 1 st May to 1 st October. The connectivity matrix K ij : South Side North Side Mainland North Side South Side The scale is log count normalized by area Patches whose particles WENT TO Santa Catalina Island Numbers to and from Santa Catalina Island 1995 Normal Year: 1997 El Nino Year: (The white island) Patches whose particles CAME FROM Santa Catalina Island Destination How to do it: Velocity Field Y t+1 = Y t + (V t * dt) 2D (surface only) velocities. Generated from an assimilation model from Lie-Yauw Oey and Charles Dong (Oey L, 2004). 5km resolution, daily for the period 2 nd January 1993 to 28 th December 1999. Simulate Larval Dispersal Particles represent larvae as passive water following parcels advected within our velocity field. 150,000 particles released over the entire integration period. The advection scheme is as follows: X t+1 = X t + (U t * dt) Source South Side North Side Mainland North Side South Side 1995 1997 A difference between years? Between climate regimes? Source and Destination Strength: 1997 Over the entire model period I can order the patches according to who was the best source of settled particles and who was the best destination for settling particles. Which patches were the best sources Which patches were the best destinations km Because the patches are irregularly shaped I have to normalize by area: Acknowledgments Bob Warner, Steve Gaines, Bruce Kendall, Chris Costello, Heather Berkley Brian Kinlan, Tim Chaffey, Chantal Swan, Mike Robinson Reference: Oey L-Y, Winant C, Dever D,Johnson W, Wang D-P. JPO (2004), 23-43 Source (j) Destination (i) Number of particles in competency window (N ij ) Numbering 1:23 - Mainland 24:35 - North shore Islands 36:47 - South shore Islands 48 - Santa Barbara Island 49 - Santa Catalina Island