Movements, Growth, and Mortality of Chesapeake Bay Summer Flounder Based on Multiple Tagging Technologies.

摘要

The research projects presented in this dissertation used multiple tagging technologies to examine the movements, growth, and mortality rates of summer flounder tagged and released in Chesapeake Bay. In the first two chapters, I used acoustic, archival, and conventional tags to examine the behavior of summer flounder on different spatial scales. Investigating the movement behavior of individuals on different scales is an important step towards understanding how large-scale distributions of a population are established. Based on the observed behaviors of summer flounder, I hypothesize that the movements of these fish are primarily related to foraging behavior while they are resident in Chesapeake Bay. In the third chapter, I use growth models to investigate hypotheses regarding recreational angler noncompliance with minimum size regulations in Virginia. Angler noncompliance with management regulations can severely degrade the ability of fishery managers to prevent overexploitation of fish populations. Using a growth model fit to recreational angler mark-recapture data, I demonstrate that recreational anglers in Virginia responded to changes in summer flounder management regulations, but considerable levels of noncompliance were detected in years when management agencies drastically increased the minimum size regulations. In the final chapter, I attempt to estimate natural and fishing mortality rates of summer flounder using conventional mark-recapture data collected by an angler tagging program. These mortality rates were estimated using a Barker model, which is a generalization of the Cormack-Jolly-Seber tagging model. Results from this study indicated that sublegal summer flounder experience different emigration or mortality processes than do larger fish. Furthermore, handling and tagging mortality rates of summer flounder were much larger than the recreational discard mortality rate currently used in the stock assessment, implying that the recreational discard mortality rate should be reexamined. The research presented in this dissertation provides information that could be used by management agencies to further understand the behavior of summer flounder, and how to most effectively manage this population.