Two-species model for spatial distributions of sardine and anchovy: A comparison with real data

We present a study of pattern formation in a setof two coupled equations modeling two competing species. Weconsider generalized Lotka-Volterra equations in the presenceof a multiplicative noise which models the interaction betweenthe species and the environment. The interaction parameterbetween the species is a random process which obeys a stochasticdifferential equation with a generalized bistable potential in thepresence of a periodic driving term, which accounts for theenvironment temperature variation.We find noise-induced spatialpatterns with strong anti-correlation between the two species.We compare our theoretical results with the experimental dataof the spatial distributions of anchovy and sardine abundancescollected during an oceanographic campaign in the Strait ofSicily. Preliminary analysis show qualitative agreement betweentheoretical and experimental results.