Caroline Ton's internship at RSMAS

by Elizabeth Babcock, on July 3, 2013

Caroline Ton's thesis involved conducting an analysis of how the movement of spiny lobsters between fished and unfished zones can bias the estimates of abundance and fishing mortality rates from fisheries data. We used an individual-based model (IBM) of lobster movement built by Ph.D. student Bill Harford to generate simulated fisheries “data” under a range of scenarios about movement of lobsters, and the distribution of fishing effort. Caroline then applied a fisheries stock assessment model to the “data” generated by the IBM to determine how well the true abundance and true fishery mortality rate could be estimated. Interestingly, she found that abundance (in the fished zone) was fairly well estimated even with high movement rates, but that the fishing mortality rate estimates were quite biased with large amounts of movement. Her results will help us estimate how much bias there may be in our estimate of an appropriate sustainable catch level of spiny lobsters at Glover’s Reef.