Regional Analysis of Florida's Gulf and Atlantic Stocks of Red Drum

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Regional Analysis of Florida's Gulf and Atlantic Stocks of Red Drum
August 2010
Fish and Wildlife Research Institute
Florida Fish and Wildlife Conservation Commission

Introduction

Early research on the population structure of red drum indicated that there were only slight genetic differences between fish in the U.S. Gulf of Mexico and those in the U.S South Atlantic region. The currently accepted meta-population structure is somewhat different and is based on findings from more advanced genetic analyses that appear to complement the findings from tagging studies. Genetic evidence suggests that estuarine-specific populations of red drum can occur and that these show some exchange with neighboring estuarine-specific populations but are increasingly isolated from populations that occur at greater and greater distances from their natal estuary. Most tag/recapture observations for inshore sub-adult red drum support the existence of estuarine-specific populations, showing little movement between or even within estuaries. However, there are infrequent occurrences of long-distance movement of sub-adults over fairly short periods of time and more frequent and extensive movement of adult red drum.

Under this 'isolation by distance' scenario it makes sense to attempt a more regional assessment and many states have conducted assessments for the red drum stocks within their waters. The choice of geographic scale for these assessments is often a compromise between the broad geographic scope of limited data and the desire to determine the population dynamics of red drum within specific estuaries. This potential population structuring has led fisheries stakeholders to take issue with the results of coast-wide assessments in Florida, asking for assessments that reflect a more regional geographic scale. This report includes an analysis of red drum within northern and southern regions on the Atlantic and Gulf coasts of Florida. It should be noted that this reduction in the spatial extent of Florida assessments for this species is counter to the much larger scales used for interstate fisheries management of red drum by the Gulf of Mexico Fisheries Management Council (U.S. Gulf of Mexico) and the Atlantic States Marine Fisheries Commission (South Atlantic Bight stock, SC through FL).