Interannual Climate Variability and Larval Transport from Cuban Snapper Spawning Aggregations

With rapid climate change, shifts in distributional ranges have been reported for an increasing number of species. The success of organisms at coping with novel seasonal conditions depends on the mechanisms that determine their reproductive schedules. Snapper migrate to form spawning aggregations with conspecifics at predictable locations and times as observed in many other coral reef related species. While spawning is thought to be associated with particular oceanographic features, dispersal kernels (i.e., the probability of dispersal) from these ‘hotspots’ of breeding activity are not well understood. They may vary spatially and temporally, possibly differing between spawning events, seasons, and years. More over, such timing programs may have constrain responses to changing climate conditions. An earlier biophysical modeling study incorporating currents from a single year (1984) and sequential runs centered on peak spawning months and lunar phases suggested that considerable levels of self-recruitment structured the Cuban snapper populations. Here we repeat this study over a decade of hydrographic conditions to investigate the effects of inter-annual variability in climatology on the transport pathways of snapper larvae and their dispersal kernels. In addition, in an effort to assess the impact of extreme climatic events on the persistence of Cuban snapper populations, we compute the dispersal kernel anomalies for simulated spawning and settlement events during the passage of hurricanes. This analysis reveals major pathways of larval transport from spawning aggregations and the effect of extreme events on their variance and on levels of local and regional connectivity, a component a component needed in the design of marine reserve networks.