LARVAL DISPERSION ALONG A STRAIGHT COAST WITH TIDAL CURRENTS - COMPLEX DISTRIBUTION PATTERNS FROM A SIMPLE-MODEL

The majority of marine species have a complex life cycle where the adu lt phase is preceded by a pelagic larval phase. The dynamics of the mo re obvious adult phase may be strongly influenced by the distribution and abundance of larvae. Field experiments have been unable to give a complete picture of the spatial-temporal dynamics of the larval phase. This is due to the extremely small size of the individual larvae and the environment in which they live. Here we present a mathematical mod el of the dispersal of larvae into a region consisting of a straight c oastline and a current dominated by tidal effects. Spawning is near th e coast from a well-defined site the size of a small jetty or reef and the larvae have a relatively short pelagic Lifetime. The model is bas ed on the advection-diffusion-mortality equation. Using a new analytic solution to the model, we examine the effect of processes such as the current structure, mortality, and the duration and rate at which larv ae are released, on dispersal. The model is relatively simple but prod uces surprisingly complex patterns of dispersal. This has implications for attempts to produce more complex models of dispersal and the way in which field data of larval densities should be interpreted.