Red Drum Population Assessment Study

Starting in April 2005, fisheries biologists from Florida Fish and Wildlife Conservation Commission's (FWC) Fish and Wildlife Research Institute (FWRI) began a three-year Marine Fisheries Initiative (MARFIN) research study. This study provides fisheries managers with important information on the status of red drum, or redfish, populations from Tampa Bay and nearshore Gulf of Mexico waters.  Currently, management regulations prohibit the commercial harvest of red drum as well as restrict both recreational size and catch limits. These limits ensure that adequate numbers of red drum survive to maturity and join nearshore adult populations.

Up-to-date scientific information about the red drum population is crucial for the FWC's efforts to evaluate the recovery of this once overfished species. However, the regulated status of  red drum reduces the opportunities for scientists to gather quality distribution, age and abundance information on red drum populations through recreational angler surveys only. Therefore, FWRI established this red drum study to provide much-needed information necessary to improve management of red drum stocks.

Two and a half years into this study, FWRI biologists continue to gather valuable data to improve our understanding of the life history characteristics and populations of red drum.  From the information collected, researchers can determine changes in habitat used by red drum as they mature and move from the nursery areas to offshore waters. Scientists can also estimate the size and age structure of the local populations to identify the amount and size of sub-adult fish, or fish not old enough to bear offspring, reaching maturity and moving into Gulf waters to spawn. In addition, catch-and-release studies help to determine the size of red drum caught by recreational anglers and estimates of related mortality.

During field work, biologists use standardized fishing methodologies (i.e. hook and line, haul seines, and nylon trammel nets) to collect samples. This helps ensure the health and survival of the fish collected. Researchers tag and release hundreds of red drum in Tampa Bay to study fish movements within the bay and into local Gulf waters. The tagging information also provides growth information.

In addition to the field work performed by FWRI biologists, FWRI scientists collaborate with local fishing guides who provide valuable expertise and resources. The help of these guides enhances the success and quality of the recreational angler catch-and-release mortality studies. A regional spotter pilot and a commercial baitfish operation also help to collect samples of red drum as part of this project.

Preliminary data show that sub-adult and young adult red drum do leave Tampa Bay and move into nearshore Gulf waters. Researchers and anglers report recapturing some of these fish as far south as Charlotte Harbor.

This FWRI red drum study also benefits other red drum research conducted by FWRI scientists. Project Tampa Bay, for example, studies the release and survival of hatchery-reared red drum in Tampa Bay. Scientists continue to track nearly 1.7 million hatchery-reared redfish released into the bay between 2000 and 2004.

The MARFIN methodologies and sampling efforts allow FWRI scientists to obtain thousands of additional genetic tissue samples from local red drum populations. These samples provide invaluable information in tracking the survival, movement, and growth of the released hatchery fish.

Most of the time researchers release red drum unharmed. However, it is necessary and even critical to sacrifice a minimal amount of fish to reach some of the management objectives put forth by both the federal and state fisheries management agencies. Scientists need these fish to obtain the maximum amount of data for this project, as well as for several other collaborative research efforts. These joint projects include work with otoliths (ear bones) for fish aging, muscle tissue for mercury levels, gonad tissue for reproductive research, fin clips for genetic analysis, stomach contents for feeding ecology studies, and various other organs for holistic fish health evaluations.

To ensure they waste nothing, FWRI donates all sacrificed fish to local soup kitchens and charitable groups.