Posts: 355
Location: Selkirk, Manitoba | R/T - 12/20/2023 2:48 PM
Angling Oracle,
A quote of yours from the 72lb thread:
"I have allopatric on the brain given there seems to be pike menacing some of the allopatric lakes to the SW closer to Dryden area given how many tigers are showing up. Yes, tigers look cool, but not good for the future of those lakes."
My special system that I fish has recently seen pike move in and thus Tigers show up and I am concerned. I have read where muskies in lakes lakes that do not normally contain pike are used to spawning shallower than maybe they would be if pike had been there all along. The young earlier spawning pike can feast on the muskie eggs/fry up shallow. Muskies in systems that have always had pike spawn deeper and this lessens this issue. Not sure if that is accurate but that is my recollection of what I have read.
I would be grateful if you could take some time and allow for some of your insight to flow through your keyboard to us regarding how the influx of pike that are not native to systems containing muskies can affect muskie populations.
Thank you very much.
Yes, the spawning timing likely a big issue. In the case of the sympatric systems that I fish, I have never seen a tiger and no one I personally know has caught one (they are there but rare). We catch far more pike than musky, so the musky really are spawning in distinct areas successfully in areas separate from pike. The musky fry are also successfully avoiding being predated on.
The eggs of pike and musky are significantly different and this is why pike are so successful and widely distributed across the entire northern hemisphere. Pike eggs are sticky and this allows them to spawn in marshy, mucky areas on weeds/cattails, etc and remain above low oxygen substrates and successfully hatch, whereas musky eggs are not sticky and need to be on well oxygenated substrates to get the oxygen they need to develop and successfully hatch. The difference in timing of the spawn/hatch does give pike the advantage when hatching, and likely the pike fry predate on new hatched musky where they overlap.
In an allopatric musky lake (like any other lake) all the species, from top predators like musky and lake trout on down, the food web is in a balanced equilibrium. The lake has a maximum yield (carrying capacity) of fish biomass that it can sustain based on the nutrient inputs coming in, so in terms of the issue at hand, if invasive pike colonize an allopatric musky lake, they are eating someone else's slice of the pie. Even if the prey is not directly what musky are eating (which in this case it probably is), the prey in the lake have not adapted to invasive pike in the same way they were to musky. Pike and musky are similar ambush type predators, but very dissimilar as far as temperature preferences of larger adults, and there is significant differences in the density of adults per acre of suitable habitat.
What this means overall though is that there could be shifts in the abundance and size distribution of the prey in the allopatric musky lake when pike start getting a significant foothold. The significant niche overlap in pike and musky habitat and diet preferences means they are likely directly competing for the same food and frequent the same habitat. This would also cause significant predation and cannibalism in both species, but with musky hatching later than pike, this could severely affect potential strong musky year classes. Not only could the small pike predate on newly hatched musky, they would also be feasting on their prey.
Some of the effects of invasive species introductions are predictable, but there are often top-down or bottom-up effects that may not be readily apparent. When it comes to top predators, I think the early exploitation of naive and non-adapted prey by the invasive is one of the major causes of a shift in abundance of other predators and subsequently unbalances the equilibrium of other species in a lake. So for example even if pike were not directly preying on the same big suckers that musky are predating on, the pike may indirectly affect their abundance by preying upon the sucker fry and fingerlings at much higher rates than before, or shifting their relative abundance or size distribution relative to other species such that the overall prey structure is not as favourable to muskies as prior to the pike invasion.
In general muskies and pike seem to be able to co-exist in very large lake or river systems where there is greater species diversity and a wider array of habitat and a greater prey variety. I believe in these sympatric systems musky have very defined spawning areas that they home to that are distinct from those of pike. In small allopatric musky lakes this separation is not really possible, and pike simply have the upper hand as far as reproductive potential over musky, however their cold-water spawning requirements and the cold water preference for adults limits their southern range.
A few thoughts for now.
Edited by Angling Oracle 1/6/2024 3:07 PM
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Tigers Showing Up