Experienced offshore anglers are all too familiar with having to release fish that are too small, out of season, or caught while trying to catch something else. If you catch a fish you are not going to keep, do what you can to help it survive and get back to the deep!
Healthy released fish will grow and reproduce, which benefits fish populations and the future of fisheries. For fish caught in deeper water, part of successful release involves relieving barotrauma in fish whose swim bladders have expanded during their ascent to the surface, leaving them too buoyant to descend on their own.
Physical signs of barotrauma include protrusion of the stomach from the fish’s mouth, bulging eyes, bloated belly, raised scales, and intestines distending from the anus. Survival of a fish experiencing barotrauma is dependent upon several factors, including severity of damage both from barotrauma and hook trauma, stress due to temperature changes, and landing and handling time.
There are two ways you can help fish suffering from barotrauma. Venting releases gas that has expanded within the swim bladder so that the fish can return to depth on its own. Weighted descent returns fish to capture depth quickly, allowing swim bladder gasses to re-compress naturally.
Studies show that both approaches are effective when applied correctly. Both approaches have advantages and disadvantages. Choose the one that is best for you, and make sure you know how to do it correctly.
Venting is a traditional barotrauma mitigation method that is particularly suited for situations where you must handle many fish quickly. Venting involves the use of a sharp, hollow instrument that is inserted through the muscle to puncture the swim bladder wall and release the gas that expanded within the swim bladder upon ascent. Many varieties of venting tools are available. You can also make your own from any sharp, hollow instrument. Knives and ice picks are not suitable, because they do not provide an adequate escape route for the gas.
Venting is quick, and the tools are cheap, but there is a risk of injuring or killing the fish if you don’t do it properly. To properly vent, lay the fish on its side on a cool, wet surface. Venting tools should be inserted at a 45-degree angle under a scale at the trailing edge of the pectoral fin, just deep enough to release trapped gas from the swim bladder. Never insert venting tools into a fish’s belly or back, or into anything protruding from its mouth.
Data shows that most fish caught at depths shallower than 125 feet generally heal quickly and resume normal activities within 24 to 48 hours if they are vented appropriately. Done incorrectly, the fish often dies.
Descending is another addition to the barotrauma mitigation toolbox. This method is particularly suited if you’re not sure how to vent, or in situations when you’re worried about potential predation on released fish.
Descending involves using a weighted device that attaches to or encloses the fish and forcibly sinks the fish. Returning it to depth on a weight will re-compress expanded gas within the fish’s body, allowing it to regain its natural buoyancy and swim away. Devices may fall into one of three general categories: Mouth grips, inverted hooks and fish elevators.
Mouth grips are attached to a rod and reel or hand line. They clamp to the mouth of the fish and use a pressure-sensor release mechanism or a weighted spring-release mechanism. Inverted hooks work like mouth grip devices but are inserted through the hole made by the hook. A fish elevator involves an inverted container such as a milk crate with a rope attached to the top and weights on the bottom. This creates a bottomless cage that carries fish back down to depth.
Regardless of which barotrauma mitigation tool you choose, it is always important to work quickly when releasing fish. The faster a fish gets back in the water, the greater its chances of survival. Use gear that minimizes fight time to reduce lactic acid buildup and stress, and try to be as efficient as possible on deck to ensure quick release to the water. Gas expansion continues, and barotrauma severity increases the longer the fish is at the surface.
Betty Staugler is the Charlotte County extension agent for the Florida Sea Grant Program. She is active in many areas relating to boating, fishing, and watershed/coastal living. The Florida Sea Grant College Program supports research and education activities that help Florida’s shoreline communities, industries and citizens wisely use the state’s coastal and marine resources. Contact her at email@example.com or 941-764-4346.