With increased public aware- ness of the need for sustain- able fisheries, more anglers are turning to catch-and-release fishing as a means to satisfying their desire for fishing as well as doing their part to conserve local stocks. Typically, an angler opts to re-lease a fish to fight another day. That the retention of a particular species violates a fishery management regulation could be another motivating factor. Such regulations include seasonal catch restrictions, size limits, and bag limits imposed by state and federal fishery management agencies. Catch regulations that require the release of certain individuals are based on the assumption that fish survive capture and subsequent handling; however, the effectiveness of these regulations depends on post-release survival rates.
The purpose of this article is to inform anglers of strategies to minimize capture stress and maximize survivorship in released fish. We also hope to provide some insight into the variety of techniques, tools, and tackle that can be used to assist in the safe release of your catch from the moment a fish arrives alongside the boat to the point at which it is released.
Handling the catch
When you get a fish alongside the boat that you are planning to release, take a moment to assess the situation for potential hazards, including the location of the hook. To get a hold of many inshore species, such as most bass, sculpin, and rockfish, the lower lip is the first apparent place to look. This is a safe technique if the species has relatively small, plate-like teeth, and obviously not a safe idea for toothy predators, like lingcod. Jaws of most fish are relatively strong and can support the weight of the body and provide an excellent handle for immobilizing small quarry. Similarly, the bill of a marlin or sailfish provides the angler with a great handle that acts to secure the head and help control the fish.
Many fish, including halibut, bonito, and small white seabass, will temporarily cooperate when grabbed firmly behind the operculum (gill flaps). Care must be taken not to damage the gills, as they are the primary site of oxygen exchange and are extremely fragile. Gripping the fish behind the head will typically cause the fish to cease moving and open its mouth for easy hook removal. It is important to apply firm pressure to initially grasp and keep the fish under control, while being careful not to squeeze so hard that you damage the underlying gill filaments. Inserting your fingers beneath the operculum is not recommended because even the slightest brushing of the gills could cause them to bleed, further de-creasing survivorship.
One thing that most people usually associate with handling fish is the slime layer coating the skin. What is often not considered is that this slime coat is essential for protection from bacterial infections and also assists in the maintenance of internal salt balance (osmoregulation). To prevent stripping your catch of its much needed slime coat, it is import- ant to either gently cradle your catch with a wet hand or chamois or firmly grasp it around the operculum. Often, the proper use of a release tool will allow you to completely avoid contact with the skin, leading to a very clean release. It is critical to avoid grabbing a fish with a rag, hoping to reduce handling as much as possible, as these actions typically result in the loss of this protective mucous coat. Also, when a landing net is required, it should be constructed of soft nylon or rubberized material with knot-less mesh to reduce the loss of slime as well as minimize fin damage.
Another problem associated with deck- ed fish is the effect of gravity. Many fish species do not have the internal support structures needed to offset being lifted out of the water; this is especially the case with large fish like marlin or sharks, which may weigh a considerable amount. Gravity experienced while on the deck may be enough to severely damage internal organs and stop blood flow. This is why it is not a good idea to remove really large fish from the water, even if you feel the photo opportunity calls for it.
Releasing the catch
Most pelagic species (e.g., marlins, tunas, and sharks) are obligate ram-ventilators, meaning that they cannot pump water over their gills manually and must swim forward in order to breathe. It is critical to remember this when releasing them, as a slowly forward-moving vessel will provide a better platform for releasing a fish than a boat that is stopped dead in the water.
A variety of release tools are commercially available to reduce the likelihood of handling injuries to both fish and fishermen; however, you can usually construct an effective device in your own garage. Extended hook re-movers, lip-gripping tools, line cutters, snooters (bill noose), tailers, and fish descenders can all be effective if used properly under the right conditions. If your plan is to release the fish, it is always critical that these tools are ready and easily accessible, since much of the stress and injury to the fish occurs when the fish is at the boat, waiting to be released. Extended hook removers or release poles can be outfitted with a variety of tips (V-notch, J-style bend, or pigtail) that are all effective for hook removal while simultaneously keeping the fish in the water. Release poles work by applying inverse pressure to the bend of the hook to pop the barb and point free from the fish’s mouth. They work especially well for large fish and sharks that have some weight behind them because it often requires a fair bit of pressure to pop the hook free, and release poles can also be fitted with an inset cutter blade to slice through your mono leader if the fish is not easily released or if the hook is too deep for retrieval. Shorter J-style-hook removers are also very effective for quickly popping the hook from many hard-to-handle inshore species, like barracuda. While these inexpensive “slime-hooks” can be made from a simple coat hanger or welding rod, the trigger-retractor hook- remover by Rapala is a great tool for extracting hooks from hard-to-handle fish, like wahoo. Lipper tools, like Boga Grips, are also effective release tools, especially when dealing with spiny or toothy species that you want to avoid handling. Snooters and tailers can also be helpful in controlling large pelagics by cinching down a noose through an extension pole over the bill of a marlin or the tail of a shark. Tail ropes may be helpful when trying to avoid a knock-out blow from the long tail of a vigorous thresher shark, but remember this species must swim forward in order to breathe so it is helpful to “walk” the fish forward prior to release.
An overlooked problem is the use of excessive force to break off a fish rather than cutting the line. Remember that a great deal of damage can be inflicted when trying to break the line from a fish that has swallowed the hook, as a deep-set hook will typically tear the viscera or gills before the line parts. Instead, it is much better to cut the line with the hook in its original position than to pull the line until it breaks. For shark anglers, an inexpensive pair of bolt-cutters can provide a great tool for cutting leaders and hooks without having to get too close to their teeth.
Releasing bottom fish
Every bottom fisher should also have a fish-descending tool on board to assist in sending small or prohibited species back to their deep-water habitat. It often seems futile to release a rockfish brought up with bulging eyes and a protruding stomach from an over-inflated gas bladder. However, research has shown that more than 80 percent of rockfish survived when returned to depths of 200 to 350 feet if they were returned promptly within two minutes of capture. Since mortality rates have been shown to increase the longer that rockfish remain at the surface, it is important to send these fish back down as soon as possible.
While there are some good commercial products available (such as Git-r-Down and the Shelton Fish Descender), an inexpensive and quick way to effectively sink floating bottom fish is to have a separate rod rigged with an inverted barb-less hook affixed to a large sinker. The barbless hook can be pinned through the corner of the mouth and the fish brought back to depth relatively quickly. When you retrieve the rig, the inverted hook will pop free and the fish can swim off at depth after its gas bladder recompresses. Descending a fish back to depth is easier and much less hazardous to both parties than attempting to deflate an over-extended gas bladder with a sharp needle.
It is unnecessary to deflate larger fish, like black seabass, that are having difficulty getting down from the surface be-cause these fish generally have enough power to swim down on their own. An exhausted black seabass may need a minute to recuperate from the long fight, but you can assist in this process by moving the fish back and forth in the water. Once the fish begins to recover, turn it right side-up and propel it downward with a shove. Usually, black seabass will give a couple of big kicks and dis-appear out of sight in a hurry, but you may need to give it several tries if the fish keeps going belly up.
Post-release mortality has been linked to a number of factors (i.e., fight time, handling methods, water temperature, hook type); however, it is apparent that hook location is among the most critical affecting survival. A local study investigating survivorship of juvenile white seabass revealed an overall post-release mortality rate of 10 percent and found that all observed mortalities were associated with hook damage to the visceral (gut) region. Gut hooking not only tears visceral tissue during the fight, but it can also cause osmoregulatory imbalance following the intrusion of seawater into the gut cavity. Additional tearing to the esophagus may also occur when deeply embedded hooks are removed by the angler; therefore, it is highly recommended that the angler simply cut the line close to the hook rather than attempt to remove it with pliers. In juvenile white seabass, survivorship was increased when deeply embedded hooks were left in place (60 percent survival) rather than being removed from the visceral tissue (35 percent survival). For this reason, if you cannot see the hook directly in the lip of the fish, it is good practice to simply cut the line as close to the mouth as possible, preferably while the fish is still in the water.
With that in mind, if you are planning to release your catch, it is good practice to use hooks that are made from metals that corrode quickly, such as bronzed bait hooks.
Many catch-and-release studies have shown that the incidence of deeply hooking fish can be reduced when anglers substitute standard J-hooks with circle hooks. A comprehensive review of re-search on the effectiveness of circle hooks has revealed a 50 percent reduction in overall post-release mortality rates, though considerable variation occurred among species. Use of non-offset circle hooks has been shown to be particularly effective in hooking marlin, sailfish, and tunas in the corner of the mouth, leading to an increase in post-release survival. Hooking fish in the jaw also reduces the likelihood of getting chewed off during the fight, allowing anglers to use lighter leaders, which usually equates to more hookups. While circle hooks effectively reduce the likelihood of gut-hooking fish, their curved design also makes them safer for anglers to use. Artificial lures and lead- heads also reduce the number of deeply hooked fish and are a preferred alternative to baited hooks when you are planning to release your catch. By implementing some careful fish-handling techniques and choosing the proper terminal tackle, you can help to ensure that the fish you release will indeed live to fight another day.
PIER is a non-profit 501(c)3 research in-stitute dedicated to scientific research, education and the sustainable management of the marine environment. Special thanks are offered to Mr. Thomas Pfleger and Family, the George T. Pfleger Foundation, the Harris Foundation, Tom Fullam, Lorraine Bohnet, Vicki Wintrode, and Jeanine Donley. To read more about PIER research projects please visit us at www.pier.org.