Barotrauma is injury to a fish's swim bladder or other organs caused by the change in pressure when it is reeled up from deep water; expanding gas can enlarge or burst the swim bladder.[1] It commonly affects snappers and groupers brought up from more than about 30 to 50 feet,[2][1] and a fish released at the surface without help may be unable to swim back down.[3] NOAA estimates that 61% of the fish caught by U.S. saltwater anglers in 2022 were released,[4] so release methods affect fish populations.
Signs
The FWC lists the signs of barotrauma as the stomach pushed out of the mouth, intestines protruding from the vent, bulging eyes, bubbling scales, flared gills, a bloated belly, and floating at the surface or being unable to swim down.[1]
Descending devices and venting
A descending device returns a fish quickly to depth, where pressure recompresses the gas; types include weighted inverted hooks, lip clamps and weighted boxes or crates. NOAA describes descending devices as the method preferred by experts and research, while noting that venting can also work when done properly.[3] The FWC suggests about one pound of descending weight for every five pounds of fish.[1]
Venting releases gas through a hollow, sharpened tool inserted at a 45° angle about 2–3 inches behind the base of the pectoral fin; knives, ice picks and hooks are not legal venting tools, and an everted stomach should never be pierced.[1] Federal definitions specified a descending device with at least 16 ounces of weight and 60 feet of line, and a venting tool of at least 16-gauge hollow tubing.[5]
Rules
Under the DESCEND Act, from January 13, 2022, commercial, charter and private vessels fishing for reef fish in Gulf federal waters had to carry a descending device or venting tool, rigged and ready.[5] That federal requirement expired in January 2026, and as of mid-2026 NOAA was considering a framework action to continue it.[6] In Florida state waters, a separate FWC rule adopted in 2023 requires a descending device or venting tool on board when fishing for reef fish, including catch-and-release, and requires its use on any fish showing barotrauma.[7][8]
NOAA, Florida Sea Grant and the Gulf States Marine Fisheries Commission run Return 'Em Right, a $30 million program promoting better release methods for Gulf reef fish.[3]
Survival research
A 2020 study that tracked 141 red snapper and 26 gray triggerfish released at 30–60 meters in the northern Gulf found that red snapper returned to depth with a descending device had significantly lower mortality over the first two days than fish released at the surface without venting. Descending devices made no significant difference for gray triggerfish, and large predators caused most of the deaths of released fish.[9]
Handling practices
NOAA recommends keeping released fish out of the water for less than 60 seconds, handling them with wet hands, using circle or barbless hooks and knotless rubber nets, not fighting fish to exhaustion, and cutting the line near a swallowed hook rather than pulling it.[2] The FWC says circle hooks are "90% more likely to hook fish in the mouth," and advises never holding fish by the jaw, gills or eyes and releasing them head first, facing into the current.[10]
References
- ^ ^ ^ ^ ^ "Barotrauma". Florida Fish and Wildlife Conservation Commission. myfwc.com
- ^ ^ "Catch and Release Fishing Best Practices". NOAA Fisheries, updated August 4, 2026. fisheries.noaa.gov
- ^ ^ ^ "Return 'Em Right: Angling for Better Catch and Release in Gulf Reef Fisheries". NOAA Fisheries, updated December 4, 2025. fisheries.noaa.gov
- ^ "Recreational Fishing: For Recreational Fishermen". NOAA Fisheries. fisheries.noaa.gov
- ^ ^ "NOAA Fisheries Reminds Reef Fish Fishermen of DESCEND Act Requirements" (FB22-001). NOAA Fisheries Southeast Regional Office, January 13, 2022. fisheries.noaa.gov
- ^ "Continuation of Management Measures to Reduce Reef Fish Release Mortality". NOAA Fisheries, July 30, 2026. fisheries.noaa.gov
- ^ "FWC approves rule to help improve survival of released reef fish". Florida Fish and Wildlife Conservation Commission, February 22, 2023. myfwc.com
- ^ "Reef Fish Gear Rules". Florida Fish and Wildlife Conservation Commission. myfwc.com
- ^ Bohaboy, E. C.; et al. (2020). "Application of three-dimensional acoustic telemetry to assess the effects of rapid recompression on reef fish discard mortality". ICES Journal of Marine Science 77(1) (via NOAA Institutional Repository). repository.library.noaa.gov
- ^ "Fish Handling and Gear". Florida Fish and Wildlife Conservation Commission. myfwc.com