This page is a collection of articles (including links to off site articles) that provide information about various aspects of Muskies and fishing for them.
There are certain fishing conditions that require special precautions to be taken, or that extra care be given to the fish in order to reduce overstressing Muskies, and help minimize the occurrence of delayed mortality. The information contained in this article may help you in making a decision that could ensure that less fish die from delayed mortality.
Muskie fishermen release the majority of the fish that they catch. Because of this, there are certain steps we should be taking to ensure that we're releasing fish healthy, and in good condition. This article will try to explain how taking special precautions in various fishing situations can greatly increase the survival rate of the Muskies we release back into the lake.
Two of the main topics summarized in this article are lactic acidosis, a buildup of lactic acid that can cause abnormal heart rhythms (potentially leading to a sudden stoppage of the heart), and hypoxemia, which is a condition of an abnormally low blood oxygen level. These two issues account for a significant portion of the delayed mortality following the catch & release process. Fishermen can have some control over these issues by simply being more aware of their effects on Muskies, and by changing some of the ways in which we fish for them.
Lactic Acid is a natural by-product of functioning muscle tissue. When fish have normal blood oxygen levels, their muscles can function aerobically with very little lactic acid produced. When the supply of oxygen in their blood is depleted, more and more lactic acid is produced and they may experience numerous metabolic abnormalities. This condition is further worsened by the hypoxemia resulting from a prolonged fight in water low in dissolved oxygen, or from long periods of air exposure while the fish is handled and photographed.
Hypoxia means low oxygen, and refers here to a fish's lack of obtaining adequate oxygen. This lack of oxygen causes their pH level to decrease and they become more acidic. That in turn leads to the interference of oxygen getting delivered to the tissues, such as the heart. As the heart becomes hypoxemic, it becomes more susceptible to abnormal rhythms. In periods of pronounced hypoxemia, the heart may even cease to function normally, possibly resulting in the death of the fish.
Many Muskie fishermen believe in using stout tackle and fighting the fish quickly without over-stressing the animal. When fighting a fish on the line, lactic acid begins to build in their muscle tissue. The longer the fight lasts, the higher the level of lactic acid produced. Once the level of lactic acid reaches the "point of no return", it may cause the fish to die. They may swim away at the time they're released, but can often die many hours later.
Higher water temperatures can magnify the oxygen and pH imbalance in the fish, and this increases the importance of shortening the fight. To reduce lactic acid levels and restore the normal pH of the blood, exhausted fish need oxygen fast, and the only way to get oxygen to the fish quickly is by allowing water to flow through its gills. Therefore many fishermen are now choosing to simply unhook the fish in the net, to avoid handling them at all. Unhooking and releasing Muskies in a timely manner will allow them to recover much sooner, and could mean the difference between life and death for the fish.
As most anglers know, water temperature is the main factor in determining how much oxygen is available to the fish. Because warm water isn't capable of holding as much dissolved oxygen as cold water, lakes with low oxygen levels can also increase the occurrence of hypoxemia in angled fish, potentially increasing delayed mortality. Many serious Muskie fishermen will not fish for Muskies at all once the water reaches certain temperatures, such as 80 degrees. In the warm summer months when water temperatures are highest, many Muskie anglers choose to pursue other species of fish that are less sensitive than Muskies to the effects of low dissolved oxygen levels.
Fishing in high winds can also increase the risk of delayed mortality, especially if you're fishing alone. It may be quite difficult to control the boat while playing the fish, which can prolong the fight time and increase the occurrence of lactic acidosis. Concurrently, if the water temperature is high, the fish may also become hypoxemic. Fishermen should strongly consider whether they should fish these locations in these scenarios or choose a different approach.
As Muskie fishermen, we have a great deal of control over many of the factors affecting delayed mortality, simply by limiting the amount of time we keep a fish out of the water. While the incidence of delayed mortality has been estimated to be in the range of 5-30% the exact figure can never be known, as there are many determining factors. Therefore we recommend that every effort be made to keep delayed mortality deaths to a minimum.
There are many other situations that also require taking precautions to help minimize the risk of delayed mortality, such as targeting deep-water fish. To achieve neutral buoyancy and have the ability to stay at any depth it may want to, a Muskie has to be able to take gas into the bladder and let gas out of it. When fish are rapidly brought to the surface from deep water, they may experience a rupture of the swim bladder, possibly allowing a gas bubble to enter the bloodstream. This gas bubble could then find its way to the gills, brain, (or other vital organ) and thus block vital blood flow from the downstream tissue. This type of injury is similar to that seen in humans who rapidly ascend from deep water. In addition, if the fish is caught from water deeper than about 50 feet, it may experience decompression sickness, (the bends), just like humans do. Due to these concerns, it has been suggested that Muskie fishermen avoid pursuing deep-water fish if they intend to release them.
Certain care should also be taken to ensure the release of healthy fish when fishing at night. In many instances the water temperature will be more beneficial to the well being of the fish in the cooler evening hours, but there are other issues that come up. You'll want to make sure you're aware of the location of your release tools and also minimize the amount of time the fish is in the net.
Cold air temperatures may also have a slight effect on the Muskie. When taken from the water in very cold air temperatures, there is a risk of freezing to the fish's eyes and/or gills. Some consider it to be a concern, but at this point it doesn't seem to be a big issue.
As much as we enjoy fishing for Muskies, there are times throughout the year when it can prove detrimental to their survival for us to fish for them without first considering the scenarios we're faced with that particular day. If certain steps are taken, we can ensure that Muskies will survive and prosper for the next generation of fishermen.
A special thank you goes out to Tom Betka for his advice and assistance with this project. It was well appreciated.References
- Thomas Betka, MD, BS (Aquatic Biology) Medical Director, Hyperbaric Medicine & Wound Care, Aurora Baycare, Medical Center, Green Bay, Wisconsin
- Casselman, S. J. 2005. Catch-and-release angling: a review with guidelines for proper fish handling practices. Fish & Wildlife Branch. Ontario Ministry of Natural Resources. Peterborough, Ontario. 26 p.
This was a 3 part post by Rob Kimm in the forums at fishingminnesota.com in July of 2006. Among other things Rob is an editor for Esox Angler and an author for NextBite.com. The first part of the post consists of some very good comments by Rob, the second part is "Handling Techniques and Survival of Released Muskellunge" by MN DNR biologist Rod Ramsell. The third part is "Vertical Holds And Time-out-of-water: Critical Issues in the Handling and Release of Trophy-sized Esox" by Michael Butler. Here's a link to the original forum post.
In his post Rob was concerned that his head cold might affect the quality of his post, but that doesn't seem to have been a problem. It made so much sense and had so much good information that we asked his permission to reprint it here.
Other than reformatting the layout, highlighting a couple of paragraphs, removing the text of a couple of unrelated posts, and adding links to the original hard copy magazine and online articles, nothing has been changed from the original post.
Past issues of the magazine are available from Esox Angler The specific issue for each article is identified at the beginning of the appropriate section on this page.
Both articles quoted here (along with many others) are also available at NextBite.com in their archives section.
Coming a little late to the discussion here - was gone over the weekend.
I do have some thoughts on vertical holds I'd like to pass on. I'm sick as a dog and so loaded up on meds (I hate summer colds) that I pretty much have half my brain tied behind my back, but hopefully this will make at least some sense...
I’m not really qualified to comment on vertical holds and bass. I have heard anecdotally (from Steve Quinn at the In-Fisherman) that the 45 degree angle lip lock is actually more damaging than a pure vertical hold, but that’s about all I can say with confidence.
I can, though, speak with some confidence on the effect vertical holds have on muskies or pike. Vertical holds are really a tough issue to address. I'm the editor of The Next Bite and Esox Angler magazine, a magazine that covers muskies, pike, and walleyes. Release issues are a big deal with muskies, so vertical holds are an issue we've covered extensively in our magazine. We've wrestled with the issue in terms of editorial content, photo policy for writers, advertisers, and readers... It's something we've a lot of time thinking about.
Someone asked if there was any significant research on vertical holds and delayed mortality. There is some. There is however relatively little research directly addressing vertical holds and mortality. When I asked one very well known esocid (pike and muskie) researcher why that was the case, he said “we don’t have the time or money to study the obvious.” We have had a couple of different fisheries biologists write on the subject, such as Rod Ramsell of the MN DNR, and Michael Butler, a research biologist at the Ontario Museum of Natural History and researcher for the Ontario MNR.
Michael Butler went a little farther than I have, and asked fisheries biologists and fish physiologists from all over the world that handle larger species about vertical holds. This included some of the foremost esocid biologists from the US and Canada, plus biologists from the UK, Australia, South Africa, Germany – all over the place. Their experiences and opinions were unanimous AGAINST using vertical holds on larger fish that are to be released. The most telling comment was from a fish physiologist (I think he was from Australia). He said: “my advice to anyone who holds a fish vertically is to eat it.”
The bottom line for me is this: Given even the potential for delayed mortality (above and beyond the chances for delayed mortality even without a vertical hold – some fish die later no matter how careful we are, and that’s just how it is…), why hold fish vertically?
When things like this come up, the “may as well quit fishing and join PETA” argument inevitably gets put forward. Sorry – that argument doesn't hold water. It's a reduction of the real issue to the absurd. The real issue is an ethical one, to me at least. If I' going to release a fish, doesn't it make sense to handle the fish in a way that makes that release most successful? Some handling of fish is a necessity. But there’s nothing in the process of releasing a muskie or pike that requires the fish to be held vertically. There’s no justification for it beyond having the fish look good in a photo. To me, that’s not a good enough reason to risk immediate or delayed mortality, or long term physiological damage to the fish. Not using vertical holds doesn't preclude photos – horizontal or semi-vertical holds with one hand supporting the fish’s side are more than possible, or just shoot in the water release shots.
As I said, I can’t speak to bass, but for pike or muskies, it’s a pretty clear cut case. Given the high potential for negative effects on the health and survivability of released fish when they’re held vertically, there’s really no excuse to do it.
I’m going to dig through my archives and see if I can find the articles I referenced here. If I can, I'll post them here.
Hi - As promised, the articles I mentioned - IF they don't overflow the buffer on post length...
The catch and release of harvestable-size muskellunge has been instrumental in perpetuating populations of this highly prized sport fish throughout its range. The importance of this practice is magnified by two basic occurrences that face today’s fisheries managers. First, muskellunge are a low-density predator even in the best of North America’s waters; and second, the targeted angling pressure for this species is higher than is has ever been, and it is increasing at an alarming rate. As the popularity of muskellunge fishing continues to grow, the practice of catch and release will become even more critical in maintaining populations of this magnificent animal.
Unfortunately, in the 20-plus years that I have been involved in the production and management of this fish, one thing that has become painfully obvious to me is that the survival rate of angler caught and released muskellunge is not as high as we all would like to think. During this time period, I have seen Minnesota’s muskellunge resource rise to levels that have generated international attention. As a result, I've come to appreciate the significance of a line from one of my favorite movies, "If you build it, they will come." The "they" in this case are muskie anglers of all skill and experience levels, both resident and non-resident. While the growth of this fishery has generated many new recreational and economic opportunities in this state, it has come with a price. I have personally recovered and autopsied hundreds of dead muskellunge and hybrid muskies from the waters in this part of the State. While the recovery of these fish has provided some valuable information, it has also shown the effects of poor handling of fish that have been caught and subsequently released by anglers. In many cases, it was easy to determine exactly where the fish had been held firmly and how the angler’s hands were oriented by the bruising of tissue resulting from pooling of blood from ruptured vascularization and the damage to skeletal structures of the body and gills. A synthesis of some of the injury observations resulting from autopsies of these recovered angling mortalities form the basis for many of the potential handling problems discussed in this article. In one of the state’s muskellunge brood lakes, I had tagged the fish from the earliest stocked year classes and monitored them during their adult life span. While I had the opportunity to handle these fish and collect their gametes for multiple years, one alarming fact has stood out during this time. I have yet to recapture a single tagged fish whose number has been reported as being caught and released by local anglers! While I am a firm believer in the value of catch and release, one can’t help but be concerned as a result of observations such as this.
We all have to keep this practice in perspective. If we turn back the clock to the 1960’s and before, almost every legal size muskellunge that was caught was harvested. The angling mortality rate was virtually 100 percent during those times. Today, many of us can cite examples from our own experiences of angled and released fish that we know have survived and have been caught or seen again. We know that catch and release can work. But, we must also accept that not every released fish survives. Even if catch and release survival is only 10 percent, it is still better than the days that no harvestable size fish were released!
Don’t misunderstand my point here; I’m not saying that today’s survival rates are only 10 percent, when in fact they are significantly higher than that. How high are they? Well, I’m not going to try to come up with a definite number, when in fact the survival rate for released muskellunge hinges on several variables. These variables can differ from lake to lake and geographic area to geographic area. These variables can include seasonal climates, daily weather conditions, the physical properties and characteristics of water (temperature, oxygenation, etc), physical condition of the individual fish, the location and severity of the hooking injury, and the degree of physiological stress that a muskellunge is subjected to.
Other important variables that play critical roles in a fish’s survival are the handling techniques, experience, skill, and confidence of each angler who practices the release of their catch. The point that I do want to emphasize is that the survival rate of released muskellunge is not as high as we would like to believe!
How can we improve the survival of the muskellunge that we release? As one who handles hundreds of adult muskellunge every year, both on and off the job, the answer is quite easy: when handling caught fish, the welfare of the fish must come first. That means we, as anglers, have to "check our egos at the dock," and minimize the stress that we subject these fish to. One of the most important ways to do that is for every angler to improve their fish handling methods.
There are dozens of stressors that fish are faced with and endure every day of their lives. Angling is an unnatural stress event that they are subjected to as a result of we, as anglers, partaking in the pursuit of a sport that we enjoy. I would hope that it is intuitively obvious to all muskellunge anglers that the best way to maximize the survival of angled fish that they intend to release is to keep them in the water! Unlike us, fish are unable to utilize oxygen from the air for respiration. They need to be in water to respire dissolved oxygen. When fish are removed from the water, they are unable to breathe and become significantly stressed in much the same way we would be stressed if our heads were submerged under water. With this in mind, it should now be clear to all anglers, regardless of experience level, that the best release practice to maximize your catch’s survival is to keep your fish in the water while it is in your possession. By doing this, you will minimize the recovery time required for that fish to return its body chemistry to equilibrium levels. Also, the gill lamellae on the gill filaments are very fragile tissues. When removed from the water, they tend to collapse and are vulnerable to temperature extremes that can result in the dehydration or freezing of these delicate structures. Damage to these tissues can inhibit a fish’s ability to respire efficiently upon release. To avoid injury to these structures, an angler’s conquest can still be documented by taking a photo of the fish in the water as it being released. If you want to impress the better muskie anglers in this world, show them a good photo of a water release!
If you haven’t graduated to the level of total water release yet and still need to hold that fish up to impress your friends, then you should at least be conscious of minimizing the time that you have that fish our of water. Remember, you have just subjected that fish to exhaustive exercise while it was on the end of your line. That exhaustive exercise has resulted in an oxygen deficit in its circulatory system. The cells in its body that have been doing all the work to attempt escape are demanding oxygen at increased levels. The only way the fish can get that oxygen is from the water. Get the picture? If you are having trouble visualizing the problem, then let’s try using you as a comparison. Run around the block 3 times, and when crossing the finish line, have your best friend dunk your head under water as you are gasping for breath. How many pictures do you want me to take to commemorate this event for you? The physiological stress that your catch is being subjected to is similar...
If you are angling during the summer months, the recovery of fish subjected to exhaustive exercise is complicated by an inverse physical relationship between water temperature and dissolved oxygen. The higher the water temperature, the less dissolved oxygen water is able to hold in solution. Fish, being cold-blooded animals, have metabolic rates that increase as water temperature increases, thus increasing their demand for dissolved oxygen. Now let’s take these thermally stressed summer fish and examine the effect of the exhaustive exercise it has been subjected to on the end of your line. Your angled fish is now demanding oxygen at an even higher rate than normal, but the warm water has less dissolved oxygen available to that fish for its recovery. The end result is, it will take much longer for that fish to intake the level of dissolved oxygen needed for recovery than it would in cooler water conditions. To put this in perspective in our human example, this would be a similar effect to our runner going around the block three times while on top of Pikes Peak in the Colorado Rockies during the summer. The air available for the runner to recover from exhaustive exercise at that altitude is also greatly reduced, and his recovery time will also be increased significantly. If you take your mid summer fish out of the water, let’s not forget the "head-dunking" that awaits you from our previous example. How many more pictures would you like me to take for you now?
Beyond oxygen deprivation, removing fish from the water can have other hazards for successful release. If your fish must be removed from the water, then its body should be supported as much as possible. It comes from a medium that is denser that the air in which we live. The water medium of a fish’s world provides support for its body. Without that support a fish becomes susceptible to other physiological stressors.
Quite simply, the worst type of out-of-water handling is the vertical hold. A vertical hold exerts a significant amount of stress on the fish’s mechanical physiology. For the average healthy muskellunge, approximately 5 to12 percent of its weight is in the skull. The remaining 88 to 95 percent of the weight is comprised of the trunk musculature, trunk skeleton, skin, and the viscera. The larger the fish, the higher the percentage of non-skull body weight within that range. This is due to the fact that, at a certain point in their life (approximately 42 inches in length), adult muskellunge tend to increase in size proportionately more in girth than in length. The primary supportive connection of all this body mass is the muscle and ligament connection of the first cervical vertebrae with the base of the skull. Very little support is provided by the connective tissue on the underside of the head in the vicinity of the isthmus. As a result, a fish held (or hung) vertically has a tremendous amount of gravitational stress upon its mechanical physiology. This can best be seen by the amount of stretch of a fish’s length when it is held vertically. A 39-inch muskellunge, measured laying flat on a measuring board, will measure between 40 and 40.5 inches when held vertically; a 48 inch muskellunge will measure between 50.5 and 51 inches under the same conditions. This increase in length results from the stretching of connective tissues between some of the more anterior vertebrae and the articulation of some of the weakly "hinged" areas and skeletal structures within the skull (see figure A).
Using gill net mortalities or recently deceased angling release mortalities that I have recovered, I have demonstrated this physiological effect on Esocids to several student interns and new employees that I have been assigned to train over the years. By showing them this physiological effect first hand, I feel it has helped all of them to become better handlers of the fish they will be working with during their professional careers.
While a brief vertical hold of a muskellunge may not be lethal in all instances, the longer a fish is in this position, the more likely it becomes that damage to the spinal column or its connection to the base of the skull will occur. Muscles in the critical areas will resist the pull of gravity on a fish’s mass briefly, but fatigue quickly causes those muscles to relax and put excessive strain on vulnerable connective tissues. Should a fish struggle or start to shake while in this vertical position, than permanent damage that will result in mortality of that fish becomes virtually guaranteed. The vertical hang is akin to the effects of hanging a "rustler" in the Old West. Whether it was on a gallows or on horseback, once the support for the victim’s body was removed, the end result was the same. If the human body, whose head-to-trunk weight proportions are similar to those of Esocids, can’t take this vertical hanging stress, how can we as sportsmen expect a muskellunge we intend to release to fare any better?
The amount of pull on the muscles and fragile bones of the operculum (gill cover) can also be a concern on vertically held fish. Injury to these mechanical structures can have negative effects on a fish’s ability to feed and respire normally. As mentioned previously, gill lamellae are extremely sensitive structures involved in the acquisition of dissolved oxygen from the water for respiration. When I see an angler with a hand inserted into this delicate area to hold a fish up, it gives me cause for much concern. This area of a fish’s body did not evolve as a "grab handle" for sportsmen. Very few anglers have enough of an understanding of the structure and physiology of this area to go around sticking their "paws" in the gill aperture. If your hands or fingers frequently get scrapped or cut grasping a fish in this area, then guess what…you’re doing it wrong! Some anglers wear a glove to protect their hands from these annoying little nicks. Anybody care to guess what’s wrong with this picture? Yep, you just increased the "bulk" of the hand you are inserting into this area of fragile structures and limited space. I've seen many dead muskellunge with damaged gill arches and clubbed and necrotic gill filaments and lamellae as a result of poor handling by their captors.
As far as damage to the internal organs on vertically held fish, this is usually not a life-threatening situation, due to the elasticity of the organ tissues. While the organs may be displaced temporarily by gravity, generally the only damage that is likely to occur internally is the possible tearing of some of the supportive mesentery.
The potential for damage to internal organs becomes more of a consideration on horizontally held fish.
Horizontally held muskellunge have less potential for permanent debilitating or lethal injury-if held properly. Don’t consider this my giving you the "go-ahead" to hold fish this way. It is just a case of the lesser of two evils if a fish absolutely has to be removed from the water for that ego photo. Fish held horizontally and supported improperly will exhibit an oblique change of the natural line of the fish. This is usually evident when one hand has a hold in the head area and the other hand in pressed against the belly of the fish in the area of the pelvic fins. This position leaves a lot of the posterior 30 to 40 percent of the fish’s length unsupported and affected by gravitational pull. The supporting hand in the area of the pelvic fins functions as a fulcrum, with a significant amount of focused pressure exerted at that point. The more horizontal the fish is held, or the longer the duration of such a hold, the greater the potential is for damage to the mechanical physiology of the muskie.
Not only can this result in spinal damage, but damage to internal organs as well.
As mentioned previously, most of the organs are very elastic in nature. However, organs such as the liver, spleen, gall bladder and the swim bladder are more fragile and can be bruised or ruptured as a result of this focused pressure. Elasticity does not imply durability. To illustrate this, let’s use the example of a balloon. If you put focused pressure in one spot in the middle of the balloon, the air inside is displaced to the volume available on either side of the pressure. But if you put enough pressure at that point, there is not enough space for the air to be displaced to-something will eventually give. In a fish, that could be a ruptured swim bladder. Even before that occurs, there is likely to be internal bruising or hemorrhaging of some of the soft tissues of critical organs. If the fish is held slightly more vertical and rotated such that the supporting hand is more on the fish’s flank, then there is less chance for injury to the internal organs. The point pressure of the supporting hand is against the dense musculature on the side of the fish, rather than against softer viscera. The best way to support the mass of a muskellunge using a horizontal hold is to use your entire supporting arm as a "cradle" (much the same way you would cradle an infant) while the control hand has a grip in the vicinity of the side of the head. Again, this is not my endorsement for you to hold a fish this way, but it is the lesser of the evil options.
In all out-of-water handling options, the loss of the protective mucus layer that protects fish from waterborne bacterial and viral infection is an additional concern. This is especially true during the warmer water temperature months when the populations of these organisms are at their peak. So, if you really want to impress me with a photo of your catch, then minimize your handling and show me that fish in the water!
I hope this article gives you all-novice and veteran muskie anglers alike-some food for thought. I’m not going to try to force anybody into changing their methods, or point a finger at specific angler’s photos saying "John Q. Muskie Angler is doing it all wrong." After reading this article, look at some of your own photos and be your own judge and jury. If all of you really care about the welfare and survival of the fish we all love to pursue, then your common sense, conscience and devotion to this magnificent animal will do the convincing for me. Some of you will have to go through what I have often referred to as the evolution of an angler and experience some of the learning steps along the way first hand. It is human nature to show off one’s achievements to our peers in an attempt to see who is the best or who’s is the biggest.
Nobody has ever been perfect in their fish handling careers, not even those of us with a biologist’s background. I know that in the over 40 years I've been handling muskellunge, I made my share of mistakes during the early years, too. I've learned from these experiences and make a point to not pay for the same real estate twice. No matter how hard we all try, muskellunge anglers as a group will never achieve 100 percent survival of every angled fish that we try to release. Each fish has it’s own different stress tolerance or will to survive. Smaller muskellunge tend to be more resilient to handling than larger ones. And sometimes, an older or a diseased fish that is in its twilight days may have just expended it's last ounce of energy to catch a meal, only to find it has a hook attached to it. No matter how much time you spend, or how hard you try, using the best handling technique in the world will not revive a fish in poor health or condition. As a group, muskie anglers have room for significant improvement in their fish handling techniques. If we really care about these fish as much as we claim, then let's do it right.
And the other...
A long-standing debate among catch and release anglers of Esox involves the merits of horizontal holds versus vertical holds for the traditional pre-release photograph. Those favoring the vertical hold correctly state that in the scientific literature, there is no documentation of harm associated with hanging a large esocid intended for release, vertically by the jaw or operculum (gill plate). Do fish handled in this manner suffer a greater likelihood of injury or delayed mortality?
Decades ago, as a student of fish anatomy, I thought the answer was a matter of common sense. The narrow symphysis connecting the lower mandibles seemed poorly designed to withstand the shearing force of a heavy, struggling pike or muskellunge. It also seemed that hanging a big fish vertically from a single hand under the operculum could injure vital tissues associated with respiration and feeding. The alternative of holding a large fish horizontally and providing support from two hands just seemed like common sense. A few years ago, I was getting so many questions about this from anglers that I set out to see just how common this sense was.
First, I solicited comments from researchers who routinely handled big muskies or pike. Among them were: Bernard Lebeau, Ed Crossman, Terry Margenau, Rod Ramsell, Bob Strand, Steve LaPan, and Arunas Liskauskas. Specifically, I asked these and other experts to comment on the risk of injury to larger (25 pounds or more) fish arising from being vertically suspended from the jaw.
While each of the muskellunge management professionals drew from a unique set of experiences, all were outspoken in recommending against the single-handed, vertical suspension of larger fish, as they felt this increased the likelihood of mechanical injury to the fish. Some-Rod Ramsell, Minnesota Department of Natural Resources, and Steve LaPan, New York State Department of Environmental Conservation-provided accounts of injuries or delayed mortality for muskellunge subjected to this kind of handling. As well, all emphasized minimizing out-of-water time, and some, a well-supported horizontal hold, if a photograph was necessary.
I should add that whenever the subject of best release practices came up in conversation with Dr. Crossman, he invariably cited an article, The Muskie Stress Factor, written by Muskies, Inc. member Rich Zebleckis, published in Muskie Magazine (Vol. 20, No. 9, pp. 11-12, 1986). The piece included a questionnaire and a scoring system that enabled the reader to assess the potential stress associated with each component (fight duration, de-hooking, handling time and methods, number and style of hooks, etc) of the catch and release process. Dr. Crossman appreciated the effective manner in which the article conveyed the ideas that (1) the stresses incurred by a fish through the C & R experience are additive, and (2), like the manner chosen to hold the fish, these individual stressors are largely under the control of the angler.
My enquiry’s didn't end with the North American Esox specialists. I posed the same question to dozens of marine biologists, fish physiologists and biomechanical engineers. These are folks who know much better than I do just what makes a big fish tick, and what might constitute mishandling. Some were authorities on gill mechanics, while others were experts on the physical properties of different tissue types. Of great relevance was the experience of the marine biologists who, as a group, had captured, tagged and released hundreds of thousands of large saltwater fishes on several continents.
Scientists are busy people. I would have been satisfied if only a third of those I wrote took the time to respond. Surprisingly, all responded, many with the view that they thought the subject was important. Some chose to comment on additional stressors, but this diverse group of scientists was unanimous in the view that the vertical hold (again of a 25-pound plus fish) by the jaw presents a much greater chance of injury to the fish. Many comments converged on the risk of injury to the fragile structures around the gills. Consistently, the muskie handlers and salt-water fish trackers were advocates of using a sling/stretcher/cradle type of device to control fish and maintain a horizontal orientation.
In the time since I polled my colleagues for their views of how best to handle Esox for catch and release, I became familiar with the recent work of our own Upper Great Lakes Management Unit of the Ontario Ministry of Natural Resources, under the direction of Arunas Liskauskas. After nearly 10 years of conducting spring spawning surveys involving the trapnetting, spawn-taking and biological sampling of medium to very large muskellunge (many fish over 50 lbs) on Lake Huron, the fisheries crews have developed considerable expertise in handling big fish. They have learned to restrain, weigh, measure, transfer, and sample fish only while they are being held horizontally in a cradle. For much of the processing, the cradle is immersed. I learned quite a bit from their experience, and I have modified my own DNA sampling protocol to conform to theirs to reduce stress and the risk of mortality to the muskellunge I handle.
I should emphasize here that the experts I consulted are not opponents of killing fish. To the contrary, the physiologists routinely sacrifice fish or apply invasive surgical procedures to their study subjects. Most of the natural resource biologists are hunters and anglers. Thus, all are members of one or more groups who have themselves been targeted by the animal-rights fringe. Their views are grounded in science and experience, not sentimentality.
Taking the responses from this diverse group as a whole, I wasn't left with the view that all fish held vertically invariably die as a consequence, but rather, that the risk of injury is much greater. This is a very significant management issue for low-density, naturally sustained trophy fisheries in Canada. Most of our World Record Class waters are characterized by having low numbers of long-lived, slow growing females distributed over vast areas of habitat. Consider Georgian Bay or Lac Seul, as examples. A seemingly small increase, say 2 percent, in annual angling mortality may result in a very significant decrease in recruitment, erosion of potential trophy production, and the decline of the stock. In the current Ontario fishing regulations, as well as pamphlets co-published by the Ontario Ministry of Natural Resources and Muskies Canada, vertical holds of muskellunge are strongly discouraged.
While the physiological determinants of delayed mortality in muskellunge have been the subject of very little research, the study of other species has valuable lessons for muskie anglers. Researchers from Dr. Bruce Tufts' lab at Queen's University have studied the blood chemistry associated with stress and delayed mortality for angled salmonids, walleye and bass. In all cases, out-of-water time has been identified as the most significant human-caused stressor. This has led to modifications of the weigh-in procedures in a growing number of Ontario bass tournaments. Bass are weighed in a column of water thus eliminating air exposure and reducing the weighing time from 30 to 5 seconds in a process that's now 'hands-off.' Very clever!
If we consider the data for other species, it's reasonable to suppose that air exposure may be the single greatest cause of post-release mortality in muskellunge. I strongly encourage muskie anglers who haven't already done so to consider foregoing the out-of-water photo session for all but 'personal bests,' particularly during warm water conditions or when red, blood-engorged fins indicate heightened physiological stress. After an exhausted fish has been removed from the water for even a few quick photographs, it usually takes minutes for it to regain physical equilibrium and minutes more to swim down through the water column. Make no mistake-this is an acutely stressed animal. These are the fish that are most likely to not recover from acute blood acidosis. Now, contrast this scenario with that of the fish played quickly to the boat and spared any out-of-water handling. These fish tend to recover their faculties in moments. If you're skeptical, try it out for a half a dozen fish next season. You'll be amazed at the difference in the condition of the fish.
Recognizing that some anglers will continue to want to remove trophy class fish from the water for photographs, a few of the researchers I canvassed suggested that during the preferred horizontal hold, contact between the fish and dry surfaces (hands, arms and clothing) should be minimized, otherwise protective mucous or "slime" could be removed. They recommended avoiding the "hug shot" where the fish is held against the chest inside the forearms, favoring instead two pre-wetted hands being the only points of contact between angler and fish.
Do we need a "controlled study to assess the effects of vertical holds" as advocated by a dwindling number of vertical hold proponents? In my grandfather's fishing prime, it was normal practice to pick up a pike or muskie by inserting a thumb and a forefinger into the eye sockets. The diminished use of the "eye socket hold" didn't follow a controlled study, legislation, or the will of an animal rights lobby. It was discarded by a new generation of conscientious, conservation-minded anglers who applied common sense to reach the conclusion that picking up fish by the eye sockets cannot be good for the fish. I believe the same ethic and intelligence is driving the trend of reducing out-of-water time and the avoidance of hanging of large fish vertically from the operculum or jaw. As for the call by vertical hold practitioners for a "controlled study," my discussions with the scientists left me certain that none of them would consider conducting such a study when the anatomy, behavior and physiology of fish-all known factors-so strongly suggest that a brief horizontal hold, or no air time at all, are the least injurious options.
It is clear that a growing number of anglers, and industry professionals, understand that our fisheries will benefit from catch and release only if it's practiced effectively. We all make choices that affect the chances of post-release survival. My discussions with experts in the fields of muskellunge research, marine fish biology, fish physiology and biomechanical engineering caused me to reflect upon-and alter-my own muskie handling techniques, both as an angler and a scientist. I hope you will consider their views, not as a rationale for criticizing others, but as food for thought as you evaluate your own handling methods and approaches to muskie conservation. Michael Butler is devoted muskie angler and a Ph.D. candidate at Trent University. He works out of the DNA laboratory of the Aquatic Biodiversity and Conservation Unit of the Ontario Ministry of Natural Resources. Michael is applying DNA markers to questions associated with the evolution, management and ecology of muskellunge, and other members of the pike family.
As you know, there are no studies out there to evaluate post-handling survival using different release techniques. During our trap net/radiotelemetry studies, we found large, adult muskellunge to be extremely sensitive to stress. Accordingly, we handle all adult muskellunge in a "stretcher." I have been an outspoken opponent of holding adult muskellunge vertically for any length of time. This is based on finding dead, tagged muskellunge subsequent to receiving letters with photos from anglers who had caught and released the fish after holding them vertically. Obviously this is anecdotal, as we don't know other circumstances associated with the "fight" and landing of the fish. A muskie's body was designed to be supported in water, and I believe that there is internal injury inflicted on the fish when it is taken from the water and held vertically.
I like to err on the conservative side. Landing nets cause problems, but are in my mind much better than gaffs. There are landing nets made with a rubber-like material which seem to be a better choice than regular knotted nylon. Cutting hooks with side-cutters makes the release process faster, and hopefully less painful (with less blood loss) for the angler. We advocate use of the "muskie stretcher", knowing well the problems associated with trying to use one.
Obviously the horizontal hold is more logical. If it is of any value, my personal procedure for handling muskellunge caught by angling is as follows:
1. Net the fish at boatside and keep fish in the water as you drift to shore. Most of the time in WI you are not too far from shore when a fish is caught.
2. Remove hooks and transfer fish into cradle. I think the cradle offers a great inlake livewell for fish while gear is untangled and you get ready for photos if needed.
3. If photos are taken the fish can be easily lifted horizontally several inches to a foot above the water for a picture. If the fish struggles, it can be lowered back into the cradle for the next try.
In our work with muskellunge we have used a sling and more recently a bag which we slip the fish into before we take it out of the water. This provides considerable support for the fish and prevents all of the potential problems [associated with handling fish]. Holding the fish by the gill cover or jaw is a very damaging thing to do to such a large fish. Most guides in the St. Lawrence are taking precautions when landing fish. They either have a sling of their own or they try, as much as possible, to release the fish without taking it out of the water.
I know this 'vertical hold', and I have always thought this could not be a very good thing for the fish! Indeed, since fishes are evolved to perform in a medium where support of body weight is of no importance, I guess that the spine is not really built to withstand large tensile forces. Apart from this, however, I also think about potential damage at the level of the head. The operculum is a delicate structure of high importance for respiration and feeding. It is operated by a series of small muscles near its joint with the suspensorium (just where the weight is supported in vertical holding!) and it forms part of an important mechanical linkage involved in jaw opening. I can thus imagine that any damage done to the opercular system (including the branchiostegal membrane) influence (at least temporarily) the respiratory and feeding performance, which must have in turn an impact on the general condition of the specimen.
Extreme care has to be taken in handling it to provide adequate support for the body, and holding a large fish vertically by its jaw is almost certain to cause serious internal injury. And to claim that large fish like muskies routinely survive this sort of treatment is probably wrong. To take the "angler's eye" view and say that the fish swam away from the boat looking fine is not saying much. It can take hours or days for internal hemorrhaging to kill a fish. The fisherman doesn't see the damage done, but serious internal bleeding, combined with the stress of fighting and landing, can quite easily kill a large fish slowly over time. My basis for making this claim is almost twenty years of experience in handling medium to large fishes in scientific research. All I am trying to say is that if you plan to release a fish to fight another day, be sure to provide adequate support (ideally a cradle) for the fish's body to prevent damage to the internal organs and mesenteries, which are far more fragile in aquatic animals than in terrestrial ones.
Dr. David Coughlin, Professor of Biology, Widener University, Chester, PA
I don't believe spinal cord or internal organ damage would be the greatest concern. Instead, I would be more concerned about damage to the connective tissue of head and to the gills. The jaws are certainly not constructed to have the body hung from them. I believe the horizontal hold is much safer position in that context.
I would tend to agree that the vertical hold of a fish is more damaging than that of a "cradle" approach. I would expect that much of the damage is in the strain brought on the gill cover, however, rather than the internal organs. Stretching of the spine may also occur, but I have seen tears at the operculum in even relatively small fishes (less than 5 lbs).
It certainly seems to me that holding a fish by the operculum (or lower jaw, as I have also seen for smaller fishes) would stretch and possibly tear muscles that are used for respiration and feeding. However, supporting the body with another hand would disturb the mucus coat of the body in that area. Overall, I would say that supporting the body as much as possible is a good idea.
The barramundi (Lates calcarifer) recreational fishery is quite big in Northern Australia and very often the fish are released after capture (and a photo). These fish grow to over 20kg and so anglers endeavour to handle these fish carefully to minimize harm. Almost all anglers use the horizontal method. I have handled fish of all sizes for tag and release and always avoided picking them up by the gills as much as possible.
I run a tag and release project from the surf along the south coast of South Africa. We tag approximately 2500 fish per year, of 15 different species. Some of these get very large. The method we have developed, and that I recommend to all anglers in South Africa who return fish, is to make a stretcher of some strong plastic or non-absorbent canvas as long as the longest fish one can reasonably hope to catch, and wide enough such that it equals the girth of such a fish.
We have tagged fish up to 55 kg using this method, and it is rare for a practised angler to keep the fish out of the water [for very long]. Small fish can be tagged, measured and released under a minute. If barbless hooks are used, no pressure need be exerted on the fish to remove the hook. Other than that, it should not be necessary to handle the fish, unless of course the fish misbehaves badly, which is rare for large fish, and can be drastically reduced by folding the stretcher so as to keep the fish's eyes out of direct sunlight.
Photographs of the fish are also improved by the stretcher, as the fish posture is more natural. Of course the angler does not get his face next to the fish, but if he is serious about release, it should not matter. Fish can also be weighed in the stretcher. We don't do this (to save handing time), unless the mass is specifically required for some research purpose.
We have had satisfactory recoveries of all species that we have tagged. The stretcher has been used from sandy and rocky shores and from boats. The latter is more difficult, depending on the amount of freeboard and the size of the waves, but practice makes perfect.
My advice to anglers who hold the fish up vertically by the gills is to eat it.
In my work with anglers during tag and release tournaments (beach fishing) I have come across similar problems you describe . In my opinion holding the fish horizontally is definitely preferable to holding it in the operculum. I will not tag fish that have been carried through the water in such way. Damage to gill filaments, mandibles etc. is far likely to be higher than injuries due to holding it horizontally. The only problem I have seen with the horizontal method is that some fish have a protective "slime layer" which then ends up at the anglers clothing. This, however, is probably better than dragging the fish in the sand…
In the mid eighties, I was working on the hatchery technology of barramundi. We wanted to produce fingerlings for stocking impoundments. My job included catching the broodstock. We angled 50 brood sized fish, weighed them by the jaw as we and our grandfathers had done, then watched the lot die over the next 10 days, despite antibiotic injections. Bloody frustrating!! I initially suspected the anaesthetic, so went out and collected another lot of fish of all sizes, and used a different anaesthetic. Again, there were a lot of deaths, but all the fish under 3kg survived. Obviously survival was related to weight. The next lot of 6 fish of 6-15kg were all weighed in a sling, and all survived.
We do know from experience that the vertebrae separate, because we sometimes hear and feel a cracking noise similar to knuckles on fingers being "cracked." I have actually measured a 35mm increase in length of a 930mm fish held vertically. We have also seen damage to the throats of fish.
We still have doubters over here, because anglers see released fish happily swim away. I am fairly friendly with the leading angling writers here, and managed to convince them and the magazine editors at the time to not publish photos of fish held vertically. It didn't take too long, so for at least 10 years, we haven't seen a photo of a fish held vertically. Please note that "tailing" fish, i.e., lifting by the tail wrist (caudal peduncle) is just as damaging, perhaps even more so, than lifting by the jaw.