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Catch-and-Release Fishing

By Erik Williams and Malia Schwartz

catch-release_fs.gif (7476 bytes)Every recreational angler in every part of the country must at one time or another release fish. Minimum size regulations require many anglers to release sub-legal-sized fish or "shorts." Rivers, lakes, and reservoirs are areas where catch and release are particularly important. The increasing popularity of recreational fishing has led to the problem of too many people, too few fish. In some areas, only catch-and-release fishing is allowed. The increase in recreational anglers is not just limited to inland fisheries. Marine recreational angling is having a great impact on certain fish stocks as well. One of the primary means of allowing all these anglers to continue fishing and maintain healthy fish stocks is catch and release. Catch and release, whether it is voluntary or required, must be done properly if it is to succeed in having the fish survive. This fact sheet should help anglers to release fish properly to increase the likelihood that the released fish will survive.

Why Catch and Release?

With the cost of a typical fishing trip, the uncertainties of success, and the appeal of a fish dinner, why should anglers want to adopt the practice of catch and release? Aside from certain regulations, such as bag limits or size limits, there are a number of good reasons for releasing a portion of the catch alive.

First, catch and release offers a sensible way to extend the fishing trip after a reasonable or legal catch limit has been reached. If the trip involves a guide or charter service, catch and release can prolong an enjoyable recreational opportunity, giving anglers more value for their money.

Second, several recent studies have suggested that as anglers gain expertise in a particular fishery or fishing technique, they often develop an interest in "limiting their kill instead of killing their limit."

Why Do Hooked Fish Die?

Fish that are caught and released may die for several reasons, but the two primary causes are stress and wounding. Stress results from the fish fighting after being hooked. Internally, the physical exertion causes an oxygen deficit in the tissues, forcing the muscles to function anaerobically (without oxygen). This causes lactic acid to build up in the muscle tissue, and then to diffuse into the blood. Lactic acid acts as an acid in the blood, causing the pH of the blood to drop. Even slight changes in pH can cause major disruptions of the metabolic processes, ultimately killing the fish. If the fish is quickly released, its blood pH usually returns to normal and the fish will be unaffected. Some fish, after a long tow, may appear to live once released, but the imbalance in the blood chemistry may kill them as late as three days after being caught. In most cases, the means of preventing this type of mortality is to not keep the fish in action for a long period of time, unless the intent is to keep it.

The other primary cause of mortality is wounding by the hook. Injuries caused by hooks can range from very minor to lethal. The degree of injury is dependent on the location of the hook wound. Higher mortalities will occur in fish that are hooked in the gill or stomach areas, while lower mortalities occur in fish that are hooked in the lip, jaw, or cheek areas. Baited hooks are more likely to result in a gill or stomach hooking that artificial lures. Treble hooks, for obvious reasons, will result in more puncture wounds and subsequently higher mortalities. Barbless hooks facilitate release and decrease "out-of-water" time, but for reasons yet unclear, may not significantly reduce mortality, especially when used with bait.

There are other kinds of physiological stress that can lead to higher mortalities in released fish. Fish may not be able to adjust to changes in pressure or to higher surface water temperatures. Also, when a fish is handled or comes in contact with dry surfaces, such as landing nets or dry hands, its mucous layers – commonly called slime layers – may be partially removed, presenting an opportunity for bacteria or pathogens to invade the skin.

Burping and Puncturing

When certain fish are brought up from depths greater than 40 feet too quickly, their swim bladders, which normally control buoyancy, can overinflate from rapid depressurization. Burping is a technique used on a fish with an overinflated swim bladder. The fish is massaged in the belly region in an attempt to release the excess air in the swim bladder. Puncturing involves using a needle or ice pick to poke a hole in the fish's exposed swim bladder. Both of these techniques are currently being advocated in other parts of the country. However, if the procedure is not carried out correctly, more damage than good may be done to the fish.

The success of burping depends on the species of fish. Some fish, such as largemouth bass, perch, striped bass, cod, hake, and black sea bass, do not have a connection from their gut to their swim bladder. If a fish's gut is not connected to its swim bladder, then burping is impossible. Puncturing is a very controversial technique. To date, there is no evidence that puncturing will increase a fish's chance of survival.

The best advice for releasing fish with overinflated swim bladders is to let them go as quickly as possible.


Catch-and-Release Guidelines

These guidelines provide basic information on the most beneficial catch-and-release methods for most small- to medium-sized freshwater and marine fish:

  1. If you plan to fish with artificial lures, such as plugs and spoons, consider replacing treble hooks with single hooks. Single hooks are quicker and easier to remove, especially when dealing with such predatory fish as bluefish and northern pike. Consider pinching the barb on your hooks, since this will make releasing the fish much easier.
  2. Plan your release strategy. Decide whether to keep or release any fish prior to angling or at least before removing the fish from the water. Familiarize yourself with any regulations in effect for the species targeted, and gather any items that will facilitate handling and releasing the fish.
  3. When a fish is hooked, use a steady, deliberate retrieval technique. This can reduce the amount of stress a hooked fish undergoes when pulled up from the depths too quickly, or when physically exhausted from an overly slow retrieve.
  4. Once you have decided on releasing the fish, avoid netting or even removing it from the water if possible. Use needle-nosed pliers to pry the hook from the fish while it is still in the water. Fish that can be lifted by the leader – the short length of line used to attach the end of the fishing line to the lure or hook – can easily be released over the rail using a "dehooker." These devices, whether homemade or purchased, are gaining in popularity in the bluefish industry – to avoid the fish's nasty teeth – and are useful for releasing a number of other species. A dehooker may simply be a metal rod with a handle at one end and a small upturned hook at the other end. If live bait or a lure is deeply embedded in the fish's gullet, cut the leader close to the fish's mouth and let the fish keep the hook. Studies have shown that fish can get rid of the hook up to 120 days later.
  5. When landing the fish, it is important to minimize out-of-water time and any fish contact with surrounding surfaces or objects.
  • Avoid using landing nets if possible. If a landing net must be used, one with a neoprene bag rather than natural twine should be used. Neoprene removes less of the fish's mucous coat.

  • Do not use a gaff!

  • Keep hands moistened. This helps prevent removal of the fish's natural protective mucous layer, and reduces the chance of subsequent infections in the fish's skin.

  • Minimize handling, particularly of the gills and soft underbelly. Gently prevent the fish from battering itself on surrounding hard surfaces. Place the fish on an old piece of foam cushion and place a wet rag or gloved hand over the fish's eye. These two actions can do much to subdue even unruly tuna and bluefish.

  1. Return the fish to the water headfirst. In most cases, it is best to point the fish's head straight down and allow the fish to plunge down into the water.


Klauber, A. 1992. Catch & Release. In: Nor'easter: Magazine of the Northeast Sea Grant Programs. Fall/Winter 1992.

Malchoff, M.H., M.P. Voiland, and D.B. MacNeill. 1992. Guidelines to Increase Survival of Recreational Sport Fish. Cornell Cooperative Extension Fact Sheet.

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