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Posts: 2361
| I have asked this before and will ask it again since we do seem to have some fish biologist input on this forum in reference to the current musky stocking discussion.
Do musky imprint at birth, or during the fry stages, and does their nursery/birth area become their spawning area of choice when they mature?
Do stocked musky imprint to the area where they were planted, when placed in a lake? Do they attempt to spawn in these areas bypassing more suitable spawning grounds for their, ahem, lol, primevil memories?
Fish obviously have some plasticity, and probably a lot of plasticity in spawning choices when undisturbed, would it be possible to change historical spawning areas simply by stocking fish in a new area or placing egg mats in a new area to provide a population with a new imprint, and possibly change the spawning ground in a major way, possibly to the advantage of the fish.
As an aside to this same question, if this does occur, imprinting and an effort of stocked fish to return to their earliest release point in a strange lake, might it be better to spread the stocking out or place the stocking in areas where there would be at least some suspicion of reproductive success rather than to dump them at boat landing X because it was the easiest place to access and unload? This question remains in my mind because there seem to be, at least strong anectdotal evidence, occurrences of this down where I fish, with certain areas producing lots of fish during the spawning and prespawn period, where, there seems to be nothing to reccommend them other than they might have originally been stocked there and returned.
Has ANYBODY studied this? It seems like a very pertinent question to me, particularly for total stocked lakes with no closed season. | |
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Posts: 178
| FIRSTSIXFEET asked: "Do musky imprint at birth, or during the fry stages, and does their nursery/birth area become their spawning area of choice when they mature? Do stocked musky imprint to the area where they were planted, when placed in a lake? Do they attempt to spawn in these areas bypassing more suitable spawning grounds for their, ahem, lol, primevil memories?"
DAVE: We must all remember that absence of evidence is not evidence of absence, but I am unaware of any published documentation to suggest that muskellunge seek the micro-location of their birth or their introduction site when they spawn as adults as a result of any type of imprinting similar to the well-known olfactory imprinting of salmonids. That does not mean that adult muskellunge do not exhibit spawning site fidelity from year to year within a lake or river. Though not well documented in the scientific literature, most experienced field biologists will tell you that spawning muskellunge select particular areas to spawn year after year.
FIRSTSIXFEET: Fish obviously have some plasticity, and probably a lot of plasticity in spawning choices when undisturbed, would it be possible to change historical spawning areas simply by stocking fish in a new area or placing egg mats in a new area to provide a population with a new imprint, and possibly change the spawning ground in a major way, possibly to the advantage of the fish.
DAVE: I am not hopeful that stocking muskellunge at a new location within a body of water would imprint them to that site as spawning adults, but your suggestion about egg mats is not without merit -- not so much to imprint the fish to a different area, but rather to increase egg survival and hatching success. I refer you to the following Abstract of a paper written by Dr. Mike Dombeck in the North American Journal of Fisheries Management in 1987:
TITLE: "Artificial Turf Incubators for Raising Muskellunge to Swim-Up Fry"
ABSTRACT: "Muskellunge (Esox masquinongy) eggs were incubated in artificial turf incubators in five lakes in Michigan and Wisconsin in 1985. Mean survival of swim-up fry from green eggs was 12% and from eyed eggs was 39%. This technique provides the manager with an economical and rapid method for raising muskellunge in lakes with inadequate spawning habitat."
FIRSTSIXFEET: As an aside to this same question, if this does occur, imprinting and an effort of stocked fish to return to their earliest release point in a strange lake, might it be better to spread the stocking out or place the stocking in areas where there would be at least some suspicion of reproductive success rather than to dump them at boat landing X because it was the easiest place to access and unload? This question remains in my mind because there seem to be, at least strong anectdotal evidence, occurrences of this down where I fish, with certain areas producing lots of fish during the spawning and prespawn period, where, there seems to be nothing to reccommend them other than they might have originally been stocked there and returned.
DAVE: I'll share a couple observations from my personal experience. When the Missouri Department of Conservation stocked 10- to 12-inch musky fingerlings at a single point of access in a cove of 8,000-acre Pomme de Terre Lake in the Missouri Ozarks, these fall-stocked fingerlings could be found distributed rather uniformly throughout the entire lake in a matter of only 3 days. It is almost as if they were compelled to take "one lap around the pool" before settling down to a specific area. IF this happens everywhere, then the location of stocking fall fingerlings is probably irrelevant in relation to any kind of imprinting to a future spawning site. In other stocked waters, such as 530-acre Hazel Creek Lake in northeastern Missouri (which I managed as a young biologist), stocked muskellunge specifically chose coves with flooded standing timber to make their spawning attempt, irrespective of the proximity of those coves to the access point where now spawning adults were once stocked as fingerlings. These observations leave me with the overall impression that stocked, hatchery-reared muskellunge seek cetain habitats, not imprinted locations, to attempt spawning as adults. Might they BE imprintable if we knew how to do it? I just don't know. By the way, in both the Missouri impoundments I just mentioned, despite documented spawning behavior, we never documented natural recruitment of young muskellunge, almost certainly because largemouth bass densities were too high (20/acre over 8" in Hazel Creek) to allow young muskellunge to survive to the end of their first summer. Musky spawning habitat seemed suitable in these waters. The bass-dominated fish community would not allow young muskies to recruit. Ohio and Illinois researchers have demonstrated this predator-prey interaction pretty conclusively.
Good questions, FIRST. It does leave me wondering if we might at least improve musky egg survival in traditional spawning areas where habitat changes have decreased the suitability of spawning substrate by adding some artificial substrate as suggested by Dr. Dombeck back in 1987. Of course, such a project would help only if poor egg survival due to habitat degradation was the bottleneck to recruitment. If the real or larger problem is fish community structure (too many predators on young muskies), then improving muskellunge spawning substrate might be an exercise in futility.
Dave Neuswanger
Fisheries Team Leader, Upper Chippewa Basin
Wisconsin DNR, Hayward | |
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Imprinting, and plasticity of spawning behaviour in musky? Dave?