Hoot Owl Restrictions for Muskellunge?
- Jason G. Freund
- 12 minutes ago
- 8 min read
While musky (Esox masquinongy) are a bit outside my area of expertise, many of the temperature-related things I have written about with trout hold true for musky, just at a slightly more elevated water temperatures. I wrote about "hoot owl" restrictions for trout and why we probably don't need them and how they would be nearly impossible to implement in Wisconsin. Hoot owl restrictions might make more sense for Muskellunge given their biology, more limited distribution, and their much lower population densities. And the ability to implement them - at least on rivers - might be easier.
Musky, Water Temperature, and Catch and Release Fishing
Musky are a coolwater fish - operating at temperatures between coldwater fishes like trout and warmwater fishes like Largemouth Bass and catfishes. The optimal range for musky growth is about 68–76°F (20–24°C) and exposure to water temperatures over 75-80°F (24-27°C) for extended periods of time are problematic. Add in the stress of catch and release angling, water temperatures over 75°F (24°C) become dangerous for Muskellunge, so just "a tick" above the temperatures we see as dangerous for trout. At elevated temperatures, low dissolved oxygen in water can become an issue.
Musky are sprinters, not marathoner runners. By that I mean, they are built for quick bursts of speed but not endurance. They are known for their short but hard-fought battles. In this burst, they build up a lot of lactic acid, deplete oxygen in their blood and tissues, and they create stress hormones.
A common refrain among anglers of all types is that they know a fish survived because "it swam away just fine". Not so fast, my friend. One of the biggest issues with catch and release for musky is what happens post release. Lactic acid continues to build, up to an hour after the release, as do stress hormones. Musky may take an hour or more for the effects of the fight to "catch up with them".
While proper handling helps, in warm water it may not be enough. Musky, if for no other reason than their sheer size, are difficult to handle. Because of their rarity, many anglers - myself included - have little experience handling them. But the "rules" are much the same as with any fish: fight them quickly, use a net or cradle, handle them as little as possible, keep them in the water and minimize the time out of water, and hold them securely so they don't fall into the boat (handle them over the water, if possible).
There is much more about the effects of water temperature and catch and release in the AI created annotated bibliographies. I did not feel like writing this blog post as a scientific paper. For more about Muskellunge temperature preferences, effects of catch and release, and their intersection, here are some sources - many of them peer reviewed:
Quantifying Catch-and-Release Mortality and Determining its Effect on Southern Muskellunge Populations
Evaluation of the physiology, behaviour, and survival of adult muskellunge (Esox masquinongy) captured and released by specialized anglers
Summer Habitat Use, Home Range, and Effect of Catch and Release Mortality on the Trophy Potential of Muskellunge, (Esox masquinongy, Mitchill, 1824), in a Southern Reservoir Population
Low catchability limits the effect of warm-water catch-and-release mortality on muskellunge
Evaluating Muskellunge (Esox masquinongy) Catch-and-Release Mortality at Elevated Summer Water Temperature
Musky Distribution and Population Density
Being the top of the food webs they occur within, musky are rare - the fish of 10,000 casts. When they are common, they are still rare. Adult musky densities typically range between about 0.10 to 0.55 fish per acre, though they may be higher in smaller "action lakes". For example, Lake Wingra, in Madison, has one of the state's highest density populations at about 1.2 fish per acre. While that sounds high, Walleye densities are typically 5 to 30 times more abundant and Smallmouth Bass 2 to 10 times more abundant. Smallmouth, can be much more common in optimal habitats. Largemouth bass tend to be even more common.
Musky distribution is more limited compared to Walleye, Smallmouth Bass, and Largemouth Bass. Musky are largely a river fish and native to the Great Lakes, lakes and rivers as far north and west as the Boundary Waters and as far southeast as the Tennessee River basin in northern Georgia and western North Carolina. I always take native range maps with a few grains of salt and add a few more grains of salt for species that are recreationally important. Often, we had moved these fishes around well before we started scientifically studying their ranges and because stocking was so prevalent, genetics often provides few insights into native ranges. The range map above looks to be missing the upper Wisconsin River above Wausau and the Great Lakes, for example.
A 2018 Wisconsin DNR publication, "Wisconsin Muskellunge Waters", describes their native range in Wisconsin as confined to the lakes and rivers of the following drainage systems:
The Chippewa River; the upper Wisconsin River (above Wausau), the Black River, the Amnicon River, and the lower Fox River, including Green Bay. The distribution has been expanded, particularly to the south, through stocking.
They have been expanded fairly greatly from their native range, both in Wisconsin and elsewhere. In that publication, they list 2085 miles of rivers and streams with Muskellunge and 667 lakes covering 588,822 acres - which does not include the Great Lakes.
For more on the biology, management, and distribution of Wisconsin's state fish:
The Case for Hoot Owl Restrictions
I made a case against "hoot owl" restrictions for trout streams in Wisconsin in a previous post. The main reasons were that they would be incredibly hard to implement - there are over 14,000 miles of trout streams in Wisconsin, few of which we have real-time temperature data for. In places where hoot owl restrictions are more common - Montana and Yellowstone National Park in Wyoming - they have more stream gages and a better understanding of real-time water temperatures. Wisconsin, like most states, relies mostly upon people being smart enough not to fish warm streams and the fact that, if they do, they are unlikely to have much success and thus, they will have no effect on trout populations.
Musky are not trout. Their biologies are totally different, though both are potentially negatively affected by warm water temperatures. Many of our trout streams have densities ranging from a hundred fish per mile up to several thousand fish per mile. In comparison, Musky densities are generally a fish to maybe a couple of fish per mile. The catch and release related mortality of a single musky is much more significant than it is for a trout population.
Because there are so many fewer populations of musky, it would be much easier to enact fishing closures. And these closures would have a greater effect than they do for trout due to the much lower density of Muskellunge compared to trout. Though, I will note, that many of the western regulations are aimed at protecting rare, native Bull Trout (Salvelinus confluentus) and Cutthroat Trout (Onchorhynchus clarkii).
There are still obstacles - for example, few of the stream gages in Wisconsin give us real-time temperature. However, that would be relatively inexpensive to change. Maybe the biggest obstacle would be the social will to do it. First, is the need to document a problem. I have no idea how much we know about population level effects in Wisconsin. The results elsewhere are sort of a mixed bag. Mortality is high in warm rivers, but catch rates are very low, so the effects seem to be fairly small. Hoot owl regulations are certainly a use of the precautionary principle. Rarely are we so forward-thinking - despite the state's motto.
The Case Against Hoot Owl Restrictions
Probably the most difficult challenge would be how to deal with these multi-species fisheries. It is much easier to close a trout stream than it is a multi-species fishery. As a person that fishes for Smallmouth Bass regularly and musky but once in my life, I would hate to have a river closed to all fishing. Not that we don't have these same challenges for other regulations. As an example, musky season in Wisconsin currently opens in northern Wisconsin on the Saturday nearest Memorial Day. Northern Pike, Walleye, and bass, at least to catch and release, opens on the standard first Saturday in May fishing opener. Thus, there are several weeks when you can fish for these fish, but not musky. I don't know how wardens enforce this regulation other than if your throwing a 10-inch bait, you are probably not fishing for pike but for musky.
What would be the choices? Close fishing on musky rivers when they are above 75 to 78°F for a day or a number of consecutive days? Do we still allow angling but only with flies or baits under a certain size that are less likely to catch musky? We have pretty good evidence that will have some effect but it will not keep musky from getting hooked, on occasion. I know that if I hook a musky on a 7 or 8 wt. means it probably takes longer to fight and because I have not handled them much, I may not be as good as those with more experience.
Like with trout, there is evidence that catch rates are so low during elevated water temperatures that catch and release mortality is quite minor. That angler success is low in warm water mitigates catch and release mortality. This is the rationale that many states use for not enacting fishing closures or hoot owl restrictions. It certainly makes management and communication about those management decisions simpler.
What About Lakes?
Lakes are thermally stratified which provides some advantages to musky and other cool-water fishes. There is almost always water of suitable temperature and dissolved oxygen for musky in larger, deeper lakes. And there is evidence that catch and release mortality is lower in thermally stratified lakes (Hartman et al. 2024) as musky are only exposed to elevated temperatures for a part of the duration of the fight. In that paper, titled "Stratification mitigates population-level effects of warmwater catch and release of Muskellunge in a southern reservoir" they write as a conclusion:
Although we observed greater survival of Muskellunge angled during the warmwater period than has been reported in previous work, their catchability was also greater, which may contribute to greater total mortality in high-use systems. Therefore, managers should consider the trade-offs between survival and catchability as functions of thermal refuge availability when developing Muskellunge management plans.
This illustrates some of the difficulties in managing fishes and, maybe more importantly, anglers and their efforts. Stonewall Jackson Lake in West Virginia is a trophy musky fishery, one of very few in the state. It is a reservoir and the state no longer has a natural lake (it once had one). It is far different than Wisconsin where we have about 550 lakes with Muskellunge. And it is far different from here in the Midwest where nearby states have ample musky fishing opportunities. Because of this, Stonewall Jackson Lake sees immense amounts of angler pressure - there are simply few other options.
The case for water temperature-related closures in lakes is maybe a bit of a different story. Musky lakes tend to have suitable habitat all summer, unlike river fisheries which may not have thermally suitable habitats.
The Wrap-Up
I can make a stronger case for hoot owl restrictions on Northern Wisconsin musky rivers than I can for trout streams in the state. The biggest obstacles are the lack of temperature information - we don't have real-time thermal gages on many musky rivers - and that these are multispecies systems whereas trout streams just have trout. I have no idea how much of this is an issue in Wisconsin as we don't really have much data on catch rates and mortality on our rivers. Lack of data always makes management decisions less likely to occur.
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