The movements of a marine copepod in a tidal lagoon. Workshop on Wetland and Estuarine Processes and Water Quality Modeling; New Orleans, LA (USA); 18 Jun 1979

The hypothesis that marine copepods are able to react to water movements in an estuary in such a way as to minimize advective losses to the open ocean is developed mathematically and tested by use of a stochastic model. Several processes are investigated as contributing to the minimization of advective less. The coupled physical-biological model used to simulate the distribution of Acartia tonsa provided numerically accurate estimates for the time histories of the physical and biological processes involved. A. tonsa appears to owe its spatial distribution in the lagoon to the combined effects of advection by currents and behavioral response to environmental stimuli, the most important being tidal advection. The resultant movements of the organisms are sufficient to minimize loses from the lagoon to the extent that it maintains an endemic population inside the lagoon which is distinct from the population found immediately outside. It was concluded that the spatial distribution of A. tonsa is heterogenous, that the patches are of the order of 240 m long by one or two metres deep, and that changes in density occur as a result of an increase in within-patch density rather than an increase in the number of patches