Modeling efforts at UCSB are conducted in conjunction with the McWilliams ROMS Group at UCLA. These efforts have played a critical role in the establishment of marine reserves in Southern California. Currently, the PISCO -UCSB group is working to incorporate biological parameters to this oceanographic model in order to assess the biological, environmental, economic, and social impacts of anthropogenic impacts in the coastal environment in collaboration with the Flow, Fish, and Fishing (F3) Group.
Larval dispersal is driven by mean currents, wind-driven Ekman circulation and coastal eddy motions as modified by the larval development time course and larval movements. In contemporary marine ecology, most models oversimplify the processes of larval dispersal and often describe it as a simple advection-diffusion process. The UCSB group assessed the roles of time-varying circulation on larval dispersal using coastal circulation simulations of the Southern California Bight (Dong et al. ; Mitarai et al. ). The results suggest that larval dispersal is driven primarily by coastal eddy motions (Fig. 1). Connectivity patterns for a single realization are highly variable because of intrinsic eddy-driven transport and variability in the winds. Mean dispersal patterns from a single release site show strong dependencies on particle-release location, season and year, reﬂecting annual and interannual circulation patterns in the Southern California Bight (SCB).
In general, mean connectivity patterns are variable and asymmetric; mainland sites are good sources while both the Northern and Southern Channel Islands are poor sources, although they receive substantial ﬂuxes of water parcels from the mainland. These variable larval distributions (or connectivity patterns) can have important consequences in stock dynamics and community structure of nearshore marine populations, and can be a dominant mechanism structuring biogeography of marine organisms. The predicted connectivity gives useful information to ecological and other applications for the SCB (e.g., designing marine protected areas and predicting the impact of a pollution event) and provides a path for quantifying nearshore site connectivity using high-resolution numerical solutions of coastal ocean circulation. These results give new insights into the nature of larval dispersal and its potential for regulating population dynamics of nearshore marine species in the coastal ocean.