Filipino Anglers Organization

You wanted to help in conserving the fishery. You caught a small grouper and decided to release it back. You haphazardly get the hook off of its mouth and quickly toss it overboard with the hope that it will grow bigger and reproduce. But did you do it right?

Did you even bother to check if the fish had a fighting chance?

Proper release of marine fishes has become increasingly important to anglers. The use of fisheries management tools such as size limits, bag limits and closed seasons as well as stronger conservation ethics have resulted in more and more fish being released. But equally important is the angler’s conscious effort to ensure that the released fish survive.

On fighting the fish and landing it
When fighting a fish which you intend to release, it is best to minimize the stress that you are causing it. Having a hook in its lip is torture enough. Don’t unnecessarily tire out the fish just to enjoy the fight. Try to land the fish as safely and as stress free as you can. Use appropriate tackle and bring the fish in quickly to reduce exhaustion. Using tackle that is too light and playing the fish to exhaustion depletes the fish’s energy reserves and can cause mortality. It also puts the fish at risk of predation. When landing the fish, avoid slamming it unto the boat. When raising the fish from deep water (25 ft or more), avoid reeling in too fast. The sudden change in water pressure will cause its swim bladder to inflate and damage internal organs.
Use a specially designed Catch & Release net with a small cloth mesh to prevent the fish scales from being damaged. The photos below are of a Rainbow Trout slowly recovering inside a cloth mesh net before its release.

Handling the fish
Minimize harming the fish further  when handling it. Use fine meshed nets to prevent damaging its scales. Wet your hands or gloves or use a wet non abrasive towel before touching the fish to prevent scraping off its protective mucous or slime. Carefully hold the fish to avoid dropping it.  If you can, you may hold it by the lip with additional support to the body. Do not hold large fish vertically by the lower jaw. In a study, 50 of 50 barramundi (a related species) died after being held this way. Avoid touching the gills as much as possible.
Know the best way to handle the fish species you are targeting and have release equipment ready. Using release tools is safer for the fish and for you.

Unhooking
Once the fish has been secured, you can then remove the hooks. There are many devices for removing hooks from fish. Commercial dehookers, forceps and long nosed pliers can be found in most tackle shops.
Debarbing your hooks will greatly make this experience easier for you and the fish. Pinch the hook barb using a long nosed plier or you can just file it off. If the fish has been gut hooked, don’t force yourself to be an instant surgeon and operate on the fish. It will stand a better chance if you just cut off the line as short as possible and leave the hook on.  The fish’s digestive system will eventually break it down (with the exception of stainless and other special coated hooks). This is a lot  better than trying to dehook the fish and ripping its guts out. Don’t think  twice about losing your gamakatsu or mustad hook over causing the fish to die with your attempts to retrieve the hook.

To minimize gut hooking in the first place, it helps to learn to strike the fish right. Furthermore, using circle hooks makes a lot of difference. In a recent study, only 1% of grouper caught with circle hooks were gut-hooked while 15% of those caught with traditional J hooks were hooked in the gut.  Avoid using kahle hooks, they are sometimes sold as circles because they also set themselves, but only true circle hooks are suitable if you want the fish to survive. Furthermore, most studies on circle hooks show that hooks with no offset are more effective in hooking the jaw than those with an offset.

Venting the swimbladder
Most fishes have a swim bladder which is a balloon-like organ that holds gas.  This is allows the fish  to maintain neutral buoyancy at the depth they are living in by controlling the amount of gas in the swim bladder. However, when a fish with a swim bladder is rapidly pulled to the surface, gas in the swim bladder quickly expands as the water pressure decreases. At or near the surface, the bladder may burst releasing gas into the body cavity. Gas in the body cavity makes a fish overly buoyant and unable to readily swim back to the bottom. Trapped at the surface and unable to maneuver, these fish are very vulnerable to predation and have low survival.
A sign of this condition is visible to anglers when the stomach of a fish is pushed out the mouth. This will look like a large pink tongue coming out of its mouth.  Another sign that a fish requires venting is when you observe the fish’s intestines protruding from its anus. Do not attempt to push distended intestines back into the fish.

Fishermen can release the gas from the body cavity by using a venting tool. The simplest venting tool is a 16 gauge needle attached to a large syringe with the plunger removed. The plunger must be removed to let the gas out. Place the fish gently on  its side and insert the needle at a 45 degree angle into the body cavity just behind the pectoral fin. The pectoral fin is the fin behind the head and the side of the body. Insert the needle only deep enough to release the gas. You can hear the escaping gas and deflation of the fish is often noticeable, hence the term fizzing. If a fish is extremely bloated use a free hand to exert gentle pressure to the fish’s abdomen to aid deflation.  If no air is coming out, check the needle first for clogs before trying another insertion.

Do not attempt to use an ice pick or a knife to release the gas. They do not work and will add to the physiological stress and injury from hooking.

Do not puncture the object sticking out the mouth of fish. This is the fishes stomach and not the swim bladder. Puncturing it or forcing it back into the fish will do more harm than good. The stomach will return to normal, in time, after the gas is released.

In most instances, using proper venting procedures will ensure the fish’s distended stomach and intestines will return to their normal state.  Researchers at Mote Marine Laboratory have found that ruptured swim bladders of snappers and groupers become functional within four days after the release and heal within two weeks.

Releasing
Leaving the fish in the water during release is best, but not always practical.  When dealing with larger fish, it is better not to boat them. Just take pictures of them in the water. They are dangerous to the boat crew and may harm themselves.
Move the fish into the shade, either alongside the boat, under the edge of a dock, or to the bottom. Cooler water contains more oxygen. If the fish is in good shape, merely hold it headfirst into the current. If it is severely lethargic, hold the bottom jaw agape and gently move the fish forward or do a figure 8 movement.  Alternatively, you can  gently support its belly, hold the knob of the tail, and face the fish towards the current. This will revive the fish by promoting water to flow over the gills. Continue until the fish is able to swim unassisted. Severely exhausted fish may require several minutes to revive. Some fish will swim a short distance, become disoriented, sink to the bottom and die, snook especially, so be observant .A large fish can be revived by towing it slowly with the boat, but make sure the fish’s head is totally submerged.

You may also use a specially designed Catch & Release net with a small cloth mesh to prevent the fish scales from being damaged. The photos below are of a Rainbow Trout slowly recovering inside a cloth mesh net before its release.

Sources: http://www.flseagrant.org/program_areas/fisheries/venting/
http://www.sciencedaily.com
http://edis.ifas.ufl.edu
http://www.prohoists.com

with valuable inputs from the ff forumers:
J.P., Steelrainbow, Oz, and Bravo3

catch and release, deep water, fizzing, swim bladder