The ScienceTypically, fish mortality is divided into two categories: initial and delayed (Arlinghaus et al. 2007). Initial mortality is often achieved when a fish is hooked in a location that causes massive bleeding and irreparable damage to fragile structures such as the gills. However, when a fish is not mortally wounded by hook location, an accumulation of sub-lethal stressors can result in delayed mortality.Once a fish is hooked and the angling event commenced, important energy stores are quickly consumed and lactic acid build-up in the muscle begins. Increases in lactate and depletion of energy stores are greatest in fish angled for long durations (Schreer et al. 2001). When a fish is finally captured it may be removed from the water for measurements and photos. This exposure to air significantly increases the time required for heart related processes to return to normal levels (Cooke and Suski 2005). Normal body function is typically achieved after an ample resuscitation period in a well oxygenated environment. Most physiological changes are magnified during periods of extreme water temperature. As cold blooded creatures, fish experience changes in water temperature throughout their bodies which can affect everything from metabolism to cellular function. Furthermore, warm water retains less oxygen which makes it increasingly difficult for fish to recover from exhaustive exercise.A successful release can be significantly influenced by hooking location, water temperature, duration of battle, and amount of air exposure. Though you may not be able to control hooking location, you can control the other factors. By taking extra steps to ensure the survival of your catch, you are helping preserve the resource so future generations can enjoy it as much as we do!
The Tools
First and foremost is some kind of landing device. Large landing nets with coated mesh can reduce fin splitting and other skin injuries. Another option is a cradle which can quickly subdue a fish, though usually takes two people to operate and may be too difficult to use when fishing solo. The Boga-Grip is another tool that allows the angler to gain control over the fish and remove the hooks quickly. Tools like these should be used only if they have jaws that can swivel 360˚, thus preventing serious damage to the jaw if a fish decides to roll. A good pair of long-nose pliers or channel locks allow the angler to reach deep into a fish’s mouth while maintaining good leverage to extract hooks; these tools also help keep the angler safe by minimizing contact with the fish’s sharp teeth. Knipex or other high quality hook cutters are often faster and less stressful than using standard long-nose pliers. If you are concerned about losing your expensive cutters while unhooking a fish, famed Ottawa/St. Lawrence River guide Marc Thorpe suggests trying this: attach a piece of nylon rope (roughly five feet long) to your cutters, tie the tag end to a keychain clip, then attach the clip to your net or somewhere inside your boat. If you lose your grip on the cutters they will simply fall away, but remain attached to your net or boat.If a pair of long-nose pliers or cutters cannot reach hooks deep inside a fish’s mouth, a new product called the Hook Pick is an invaluable tool. Its simple design coupled with an overall length of 15 inches allows the angler to push or pull on a hook wedged deep inside a fish’s mouth. Many folks employ the “Leech Lake Lip Lock” which puts the angler’s hands in very close contact with the fish’s razor sharp gill rakers and sensitive gill filaments. A glove such as Musky Armor’s “Release Glove” protects the angler’s hands from sharp gill rakers, affords the angler excellent dexterity, and more importantly minimizes the bulk of other gloves that can damage the fragile gill filaments. If crushed or torn, these filaments can prevent the fish from obtaining necessary oxygen once returned to the water. Please use caution when handling muskies near their gills.
Landing the Muskie
As soon as the fish is landed, take a deep breath and compose yourself! Make sure the fish’s head is in the water. If the fish’s head is above the water because the lure has tangled in your net begin unhooking immediately. Your goal should be to remove hooks in as little time as possible. Thorpe, who has handled hundreds if not thousands of muskies in his lifetime, notes that there are two visual queues anglers can use to determine if a fish is undergoing excessive amounts of stress. If the sides of the fish and/or the eye or eyelids turn a reddish coloration, this is may be a sign of severe stress. If the angler sees this, Thorpe advises not to remove the muskie from the water; the release should commence immediately. If you choose to take a muskie which is not severely stressed out of the water for photos and/or measurements, give the fish a little time to recuperate after removing the hooks. Immediately removing them from their only source of oxygen heightens stress and increases the time it will take for stress levels to subside. Furthermore, you must grip the fish as tight as humanly possible when handling the fish or removing them from the water. Dropping the muskie can result in serious external and internal injuries.
Air Exposure, Measurements, and Photos
If you choose to take measurements and/or pictures, your goal should be to keep the fish out of water for as little time as possible. You and your boat partner should be familiar with how your camera operates before hitting the water. Keep in mind how you hold the fish if a photo session is desired. A vertical hold can severely damage a muskie’s spinal column, gill structures, jaw bones, and internal organs as connective tissue tears and organs slide or rupture inside the fish. The longer your catch is held in this position, the higher the likelihood of inflicting damage. Therefore, it is advised that the fish is lifted horizontally out of the net or cradle and supported with fingers spread or the entire arm positioned near the mid-section of the fish to support the fish’s mass and prevent internal injury.Measuring the fish should be done quickly and with little to no air exposure. Measuring a fish vertically is never recommended for the dangers listed above plus the additional air exposure it would cause. Another popular measurement method is the use of a bump board. While this method keeps the fish’s mass fully supported, it still requires additional air exposure. I cannot emphasize enough that it is crucial to minimize the duration of air exposure as much as possible. Therefore, it is highly recommended that all measurements be taken in the water. This is the absolute safest form of measuring that can significantly minimize stress. After using a large landing net to secure the fish, Thorpe uses the built-in ruler on Frabill’s “Pro Tech Muskie Cradle” to measure fish in the water. A simple floating ruler or cloth tape would also work for in-water measurements.
The Release
The biggest mistake I see anglers make when releasing fish is when they force the fish forward and backward. This puts unnecessary strain on the fish’s fragile gill plates. Simply hold the fish upright by the base of the tail and allow it to recover on its own. Periodically release your grip to make sure the fish has gained full equilibrium and is not rolling over on its side. Once equilibrium has been achieved, let go. The less handling that takes place the less stress the fish will undergo. Do not slap the fish on the tail to get it to “take off.” This forces the fish to burst swim which is the very type of exhaustive exercise that you are trying to help the fish recover from. Remember, just because a fish swims away quickly does not necessarily mean it will survive.
Releases in High Water Temperature
When fishing in high water temperatures, everything must be done faster. The duration of the fight, the unhooking process, the handling period, and the time out of water must all be shorter. In fact, it is advised that the angler not remove the fish from the water during periods of extreme water temperature, particularly when the water is above 80˚F. If you must, Thorpe suggests limiting time out-of-water during this period to 20 seconds or less. It takes fish significantly longer to recover from exhaustive exercise during periods of high water temperature (Suski et al. 2006), and removing them from the water will only prolong the recovery period. Furthermore, there is a positive relationship between bacteria production and water temperature (Sander and Kalff 1993), increasing the likelihood that fish with lowered immune systems (as a result of exhaustive exercise) could contract water-born illnesses. A total-water-release where hooks are removed and measurements taken in the water is highly recommended. In fact, many anglers choose not to fish muskies once water temperatures reach 80 degrees, and instead switch to other species or pursue muskies at night when water temperatures are cooler.
Preserving the Resource
Humans have a responsibility to protect and care for nature’s resources. As stewards of nature, particularly as anglers, taking every step possible to ensure the successful release of your catch helps fulfill this obligation. On the spectrum of handling procedures – from harvest to total-water-release – the guidelines in this article fall somewhere in the middle. The importance of educating the public on proper handling procedures increases as the sport’s popularity increases. Our handling procedures will never ensure 100 percent of our muskies will be released successfully, but there are certain techniques you can employ that will dramatically decrease delayed mortality and keep survival rates high. Most studies on fish physiology focus on bass and trout; there are very few physiology studies focusing on muskies. Testing the effects various handling techniques have on delayed mortality is an important step in revealing what specific practices are most beneficial for the preservation of this resource. The muskie is a fish that provides great value both as an apex predator in aquatic ecosystems and as quarry to those of us who love to pursue this beast. Please practice catch-and-release with care – remember your goal is to release a healthy fish which will live to grow, spawn, and perhaps fight again!
References and Acknowledgements
Special thanks to John Underhill and Marc Thorpe for giving the author permission to use their photos.
Arlinghaus, R., Cooke, S.J., Lyman, J., Policansky, D., Schwab, A, Suski, C.D., Sutton, S.G., & Thorstad, E.B (2007) Understanding the complexity of catch-and-release in recreation fishing: An integrative synthesis of global knowledge from historical, ethical, social, and biological perspectives. Reviews in Fisheries Science 15: 75-167.
Cooke, S.J. & Suski, C.D. (2005) Do we need species-specific guidelines for catch-and-release recreational angling to effectively conserve diverse fishery resources? Biodiversity and Conservation 14: 1195-1209.
Sander, B.C. & Kalff, J. (1993) Factors controlling bacterial production in marine and freshwater sediments. Microbial Ecology 26: 76-99.
Schreer, J. F., Cooke, S.J. & McKinley, R.S (2001) Cardiac response to variable forced exercise at different temperatures an angling simulation for smallmouth bass. Transactions of the American Fishery Society 130: 783–795.
Suski, C.D., Killen, S.S., Kieffer, J.D. & Tufts, B.L. (2006) The influence of environmental temperature and oxygen concentration on the recovery of largemouth bass from exercise: Implications for live-release angling tournaments. Journal of Fish Biology 68: 120-136
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