Marine reef fish have a gas-filled organ called a swim bladder, which controls buoyancy and allows the fish to maintain a certain depth. When a reef fish is pulled up from deep water, the gas in the swim bladder sometimes expands. When a fish is released in this condition, the fish is unable to swim back down to capture depth making it difficult to survive the elements and avoid predators.
Venting tools are sharpened, hollow instruments such as a hypodermic syringe with the plunger removed or a 16-guage needle fixed to a hollow wooden dowel that allow for the release of expanded gas from the fish body cavity—enabling fish to swim back to capture depth. A variety of tools are available in bait and tackle stores. A tool such as a knife or ice-pick is not a venting tool because it does not allow the expanded gases to escape from inside the body.
How to Vent
The most important thing when handling fish for any reason, is to handle it as little as possible. Vent the fish as quickly as you can by holding the fish gently on its side and inserting the needle into the body cavity at a 45-degree angle under a scale. The area to insert the venting tool is approximately 1 to 2 inches behind the base of the pectoral fin. Insert the venting tool just deep enough to release the expanded gases. You may hear an audible release of this gas.
Venting helps release gases that may over-expand in the body cavity when fish are brought to the surface from deep water.
When to Vent
Fish taken from depths of 50 feet or more may undergo expansion of the gases in the swim bladder as they are brought to the surface at a rapid rate. If a fish cannot descend on its own, venting is a method that can be used to release the gas and allow the fish to go back down to capture depth. There is no strict formula for determining when a fish will require venting. Problems usually start to occur when reef fish are taken from depths of 50 feet or more, but there are a number of factors that make it impossible to predict an exact depth. Also, different species react differently. The change in water temperature from summer to winter can also make a big difference. There are a number of signs of this condition (Barotrauma). The signs include: protrusion of the stomach from the mouth, bulging eyes, bloated belly, and distended intestines showing from the vent. Observing one, any or all of these indicates the fish needs venting before releasing it.
Sometimes these symptoms are not readily apparent. If the fish is actively fighting and attempting to swim down it may not need venting.
Remember to only use a venting tool when one or all of the below signs of trauma are noticed. If the stomach is protruding from the mouth of the fish, do not try to vent or push the stomach back in, when the fish swims back down to depth it will re-ingest its stomach. Return the fish to the water as soon as possible and if necessary revive the fish with the head pointed downward and moving the fish forward in the water allowing water to pass over the gills.
Circle hooks are made so that the point is turned perpendicular to the shank to form a circular or oval shape. Research has found that circle hooks are 90% more likely to hook fish in the mouth instead of in the esophagus or stomach. This reduces internal harm to the fish; it decreases de-hooking time for the angler, and decreases the chances of a hook getting lost in the fish. Fish hooked in the corner of the mouth tend to fight less than fish that are hooked in the gut. Also, with the circle hook in the corner of the mouth the line is generally out of the way of the fish’s teeth making it easier to de-hook. Pictured below is an example of a J Hook (left) vs. a circle hook (right).
Non-Stainless Steel Hooks
If a fish is hooked deep in the throat or gut, research has shown that it is best to cut the leader as close to the hook as possible and leave the hook in the fish. Prolonged attempts to remove the hook often do more harm than good and because the hook is non-stainless steel, it will eventually rust out of the fish. Steel and bronze hooks are less toxic and are rejected or "dissolved" sooner than are stainless steel and cadmium- or nickel-plated hooks.
Non-off set Hooks
In Florida, it is required to use non-offset circle hooks when fishing from a vessel with natural bait for reef fish in Gulf waters. Non-offset circle hooks are those in which the end of the hook is in line with the shank of the hook – rather than being angled sideways away from the shank.
Circle Hook Tips! Try fishing with barbless hooks or crimp the barb down. Catch rates using barbed versus barbless hooks are not significantly different, but the advantage of using barbless hooks is that they are easier to remove from a fish or yourself! Also remember to not set the circle hook. After the fish takes the bait, allow the fish to run and then proceed to reel it in.
De-hooking tools are designed to remove a hook from a fish without the hook being re-engaged into a fish. De-hooking tools come in a variety of shapes and sizes to fit the need of the angler, and even a pair of needle nose pliers is considered a de-hooking tool.
De-hooking tools should be matched to the angler, the fish that are being targeted, and the vessel. If an angler is fishing from a boat with a high gunwale, the de-hooking tool may need to have a longer “shaft” or if being used on a kayak, a shorter de-hooking tool should be used. If targeting fish with large teeth, spines, or sharp barbs, use a long de-hooking tool to keep hands and fingers out of harm’s way.
If a fish is gut hooked cut the line as close to the hook as possible to avoid further damage to internal organs.
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