Mote Marine Laboratory

On the Line with Aaron Adams, Ph.D.

By: Aaron Adams, Ph.D.

Figuring out where fish are on any given day is one of the big challenges for recreational anglers. Marine gamefish also pose considerable challenges to scientists. There’s a lot of water to cover, and marine fish tend to move around a lot. Just figuring out the area that a single fish can cover in a week  — or a year — is challenging.

Adults of some species, like tarpon, can migrate long distances, such as from Mexico to Florida. Adults of other species may not be able to migrate that far, but their larvae can. Most marine gamefish spawn by a process called ‘broadcast spawning,’ whereby eggs and sperm are ejected into the open water where they mix together and sperm fertilizes egg. The larvae that hatch from the eggs can spend weeks or months floating in the open ocean as plankton before they undergo metamorphosis and move to juvenile habitats.

For most species, the habitats important for juvenile fish are different from those used by adults. Understanding how fish in different areas are related is important to management and conservation because the information is used to determine how large a geographic area must be incorporated into management of a species.

Scientists are using new technological advances, from high-tech tags to genetic testing, to figure out all of this movement. Genetics is proving to be valuable tool, and recreational anglers have the opportunity to play an integral role in this kind of research.

Bonefish research

After hatching, bonefish larvae drift in the open ocean for 42 to 72 days, giving them plenty of time to reach Florida from anywhere in the Caribbean. This means that bonefish fisheries throughout Caribbean waters are probably interconnected, a hypothesis that we’re testing using genetic sampling techniques. If it turns out they are, that could influence how species are managed.
Mote, Bonefish & Tarpon Unlimited and the Florida Fish and Wildlife Research Institute are collaborating on research using genetics to address such questions. Scientists take small clips of tissue from the dorsal fin of the bonefish for genetic analysis. The tissue grows back in a few weeks. Anglers can help by taking their own fin clips from the fish they catch and mailing them to us for genetic analysis. To help, contact me at aadams@mote.org to request a fin clip kit, which includes instructions on how to take a sample and where to send it. We hope to gather fin clip samples from Florida and throughout the Caribbean.

Red Drum research
We’re using genetics to address a different question about red drum, or redfish: Is the stock enhancement program in Tampa Bay bearing fruit? In “Project Tampa Bay,” scientists determine the genetic fingerprints for adult red drum that are captured and used as brood stock, or parents, to the new generation of juveniles grown in a hatchery and then released to the wild. Fin clips are then taken from red drum captured by anglers to determine how many may have come from the hatchery-raised fish. Genetic analysis answers the question because some of the parents’ genes are passed along to offspring. Mote and the Florida Fish and Wildlife Research Institute are collaborating on this research. So far, more than 4 million redfish have been raised in a hatchery and released into Tampa Bay with the goal of determining the effectiveness and benefits of stock enhancement in a large estuarine system.
Anglers interested in helping redfish research should contact Carole Neidig at cneidig@mote.org to request a fin clip kit.

— Dr. Aaron Adams is manager of Mote’s Fisheries Habitat Ecology Program and an avid fly fisherman. He is author of Fisherman’s Coast: An Angler’s Guide to Marine Warm-Water Gamefish and Their Habitats.

Learn more about: Stock Enhancement, Fin Clipping

We're angling for your support. We aspire to become recognized as a world leader in the fields of fisheries ecology, enhancement and management strategies. Along with clipping fins, please feel free to help us feed these aspirations.