Researchers collect detailed information on caught-and-released reef fish and evaluate survival under various conditions.
A researcher uses a venting tool to release
gas from a tagged gag’s swim bladder,
making it easier for the fish to swim
back to its normal habitat depth.
When anglers head out on the water, they could come home with a catch, reel-in and release a fish or two, or come back empty-handed. While a fruitless trip may lead to tales of the one that got away, it is the other two outcomes that allow researchers to learn more about Florida fisheries. Traditionally, surveys of recreational fishers count harvested fish during dockside interviews, where anglers can easily show biologists their catch. However, anglers often release other fish that are illegal to harvest. To account for these fish, FWRI’s Fisheries-Dependent Monitoring researchers, in a project underway since 2009, collect detailed information on caught-and-released reef fish and evaluate fish survival under various conditions.
Over the years, scientists have discovered that catching and releasing fish can lead to some uncounted deaths. Fish caught from great depths may not recover after surfacing, and internal injuries can occur when fish swallow baited hooks. Solutions are available: venting a fish’s inflated swim bladder helps it return to the bottom, and circle hooks may lessen chances of severe trauma. However, it is important to understand how anglers use these methods and to determine the true health impacts of catch-and-release fishing. FWRI researchers are tackling this challenge with the help of more than 100 charter and headboat vessel operators from Tampa Bay to the Florida Panhandle.
Each week, a scientist boards one randomly chosen boat to observe recreational hook-and-line fishing during a typical trip. The biologist records depths where the fishing takes place, the type of gear used, the numbers and types of fish caught and released, and the condition of the fish after the catch. When an angler catches a red snapper, red grouper, gag or other targeted species, the researcher tags the fish before release. A recreational or commercial fisher who catches that fish again can report the catch to FWC’s Tag Return Hotline, allowing researchers to monitor the survival of the fish. Volunteer anglers also provide information during their private fishing trips by submitting “catch cards” – postage-paid data cards that project staff hand out at boat ramps and marinas.
So far, project scientists have found that the use of circle hooks does increase the likelihood of lip-hooking—which is thought to result in fewer hooking injuries – in seven of the ten species studied. Researchers are using tag reporting data to evaluate conditions that influence the survival of released fish. For example, gag are often caught and released by recreational anglers in shallow waters, where they are more likely to live and be caught again than those retrieved from greater depths. With this information, researchers can better determine survival rates for gags released by recreational anglers and provide enhanced data for stock assessments and fishery management.