Wednesday, September 15, 2010: 2:40 PM
320 (Convention Center)
Joseph E. Powers, PhD
,
Oceanography and Coastal Sciences, Louisiana State University, Baton Rouge, LA
Elizabeth Brooks, PhD
,
Population Dynamics Branch, National Marine Fisheries Service, Woods Hole, MA
Melissa Hedges Monk
,
Oceanography and Coastal Sciences, Louisiana State University, Baton Rouge, LA
Multi-species interactions and species biomass distributions (SBDs) can be analyzed by an N-species Lotka-Volterra (LV) system of equations. We derive a statistical approximation to the stationary probability distribution of relative species biomass for a system of interacting species. The distribution is parameterized by the mean and variance of the LV species interaction coefficients and can exhibit a variety of shapes. SBDs estimated from simulated LV data provided good fits. The responses of the SBDs to simulations that incorporate fishing mortality rates are explored. Examples of SBDs using fishery-independent survey data from the Gulf of Mexico are examined using the model. We discuss how changes in species composition can be used to characterize ecosystem responses to perturbations like fishing mortality.