VIMS releases acoustically tagged flounder for study

Researchers at the Virginia Institute of Marine Science (VIMS) have released 120 specially tagged summer flounder during the past 2 weeks at 3 study sites in lower Chesapeake Bay. The researchers ask anglers to assist with the study by re-releasing any tagged flounder they catch alive as close as possible to where the fish were caught.

The study, funded by Virginia saltwater fishing license funds, is designed to determine movement patterns of flounder associated with underwater structure. It runs through the summer and into the winter. Study sites include the Gloucester Point Fishing Pier, Back River Reef, and a "non-structure" site near York Spit Light.

Each tagged fish, whether undersize or legal-size, carries a small acoustic "pinger" (small black capsule) surgically implanted in its belly cavity, as well as a 2.5-inch yellow streamer tag near the base of its tail. The tag number can be used for identification.

Each fish and its electronic data are critical to the study's results. It is just as important to live-release legal-size flounder as undersized fish. By re-releasing the specially tagged flounder, its acoustic pinger will continue to send out its unique signal. The ultrasonic signals from each of the fish tagged at the study sites are saved in the memory of buoyed receivers.

Anglers who catch a tagged flounder should:

  • Handle the fish carefully when removing it from the hook.
  • Record the tag number, found on the end of the yellow tag, and release the fish alive with the yellow tag intact.
  • Call the VIMS phone number (804-684-7588) on the tag, sharing any information on the fish's appearance and condition (e.g., slight bleeding). A reward (flounder cap) is offered for reporting the catch and release of the tagged fish.
  • If no one is able to directly answer your call, please leave a detailed voice message. This should include the flounder's tag number and overall condition, the date and location of capture, your name, mailing address, and a phone number where you can be reached at a time convenient to you. The researchers will get back in touch with you to verify your information.
  • If you capture, but seriously injure (gut-hook, much bleeding, etc.), a specially tagged flounder, please keep it, even if undersize, and call VIMS at 804-684-7588. Marine Police Officers are aware of such special situations. But to avoid violation of flounder regulations, the retained fish must have the special yellow tag in place. If you are checked by a MPO, the officer may take control of the fish for the study.

The study was designed to answer questions raised by results from conventional tagging of flounder by trained anglers in the Virginia Game Fish Tagging Program. Since 2000, these volunteers have tagged more than 30,000 flounder, mostly at fishing piers and other structures. Each year, anglers report a number of recaptures of these fish (nearly 3,000 to date). Many recaptures occur at the pier or structure site where the flounder were first tagged (including bridge-tunnels, rock jetties, and artificial reefs). Most angler reports are single recaptures of flounder, but multiple recaptures of the same fish have also been documented.

Flounder recaptures regularly show fish at the same site several weeks to several months after being tagged. Such data suggest that some flounder are remaining near structure sites throughout the fishing season, but whether the fish continually use the site is unknown. The researchers would like to determine if the flounder are simply returning to the structures repeatedly as a feeding base during the season, or if they are showing strong site fidelity, remaining near the structures throughout spring, summer, and into the fall. The latter scenario would imply that the structure sites are important feeding and concentration areas.

"Our study is designed to help solve this riddle," says Jon Lucy of the Sea Grant Marine Advisory Program at VIMS. Lucy, who is assisting Dr. Mary Fabrizio with the project, is also co-director of the Game Fish Tagging Program. Fabrizio, an Associate Professor of Fisheries Science at VIMS, is coordinating the acoustic tagging study.

"This study takes a big step beyond conventional tagging data," says Fabrizio. "By using acoustic pingers and underwater receivers at the three study sites, we can monitor the location of the tagged fish around the clock. We want to determine if the apparent site fidelity suggested by earlier tagging studies is 'real' and to estimate how long flounder are using the structure sites during the fishing season."

By building on the Game Fish Tagging database, the study should help verify if flounder consistently use structure sites over periods of weeks to months during their stay in Chesapeake Bay. The acoustic monitoring of the fish should also shed light on whether small fish behave differently than large fish.

Fishing piers and artificial reefs may regularly provide feeding areas for large concentrations of flounder, at least for undersized fish. As such, these areas may warrant special consideration. For example, fishery managers may want to focus more on flounder when expanding or modifying artificial reefs. Similarly, construction schedules at certain structure sites might give more consideration to flounder. When tracking, monitoring, and mapping finfish resources, researchers and managers may find that structure sites ultimately prove to be more significant for flounder than once thought.

"Through their tagging efforts, Virginia's saltwater anglers have already helped to better understand habitats important to undersized flounder," says Lucy. "Now we're asking them for more help by releasing alive specially tagged flounder for this study. The objectives of both efforts are to better understand and reduce impacts on an improving recreational flounder fishery."