The Muskellunge

Picture By: Virgil Beck, for additional information visit Wisconsin Sea Grant web site.


Scientific Name: Esox masquinongy

Common Names: muskellunge, muskie, musky

Mukellunge Distribution and Identification

The muskie, a member of the pike family (Esocidae), is a top predator in freshwaters of the Great Lakes region. The natural range of the muskie spans from north to south from Tennessee to mid-Ontario, and from east to west from New York to Minnesota. Muskie can reach lengths of over 50 inches and weights of over 50 pounds. Their appearance is streamlined, with their dorsal fin located directly above the anal fin, and their mouth is equipped with sharp canine teeth (Trautman 1981). Muskie generally fall into one of, or a combination of, three distinct color phases: spotted, barred, or clear (no markings)

Muskie from the upper Mississippi watershed and Great Lakes, including Lake St. Clair, are generally spotted, with most inland muskie in the Midwestern United States falling into the barred or clear phases. As with most species, though, color and markings are not the best way to identify the muskellunge. Northern pike (Esox lucius) is a closely related species in the pike family that reaches similar sizes as muskie, and could easily be confused with muskellunge. To distinguish between northern pike and muskie, the head must be closely examined. Muskellunge have six or more pores on the underside of their jaws and the upper half of their cheeks are scaled, while northern pike have 5 or fewer pores and entirely scaled cheeks. A final anatomical feature to check is the tail, with muskie tails being more deeply forked and northern pike tails being more rounded off. Hybridization between muskie and northern pike is possible, with the resultant tiger muskellunge displaying characteristics of both parents. Tiger muskie generally have both bars and spots, making it appear more like a muskie than a northern pike, but the tiger muskie tail is usually rounded like the northern pike (Figure 1). For more thorough anatomical descriptions see Trautman (1981).



Figure 1: Muskie, northern pike, and tiger muskie identification. Artist- Virgil Beck, for more information visit the Trent University web site.

Unlike many coolwater, freshwater species it is possible to visually determine the sex of mature muskellunge. In adult female muskie the urogenital region resembles the shape of a pear, while in adult male muskellunge the shape of the region resembles a keyhole (Figure 2) (Lebeau and Pageau 1989). Sexually dimorphic growth occurs with muskellunge, as females reach larger ultimate sizes than males. Another interesting fact about the muskellunge is that there is evidence that muskie have a different sex-determining system than northern pike. While northern pike appear to use an XY system similar to ours (with males being XY and females being XX), research by Dabrowski et al. (2000) uncovered evidence of a WZ system (with males being ZZ and females being WZ) in muskellunge. Simply stated, in northern pike, males determine the sex of offspring, while in muskie, females determine the sex of offspring.



Figure 2: Picture of female (left) and male (right) muskellunge urogenital region (Lebeau and Pageau 1989, for additional information visit the Trent University web site).

Mukellunge Biology

Muskellunge and northern pike many times inhabit similar habitats, and research in Minnesota revealed a few interesting findings. Muskie, in the absence of northern pike, tend to reproduce in the same shallow, weedy areas that would normally be dominated by northern pike spawning during the spring. However, in the presence of northern pike the muskellunge tend to spawn in slightly deeper water, yielding the more preferred habitat to the northern pike. The presence or absence of northern pike also appears to impact ultimate growth of muskellunge. Muskie inhabiting waters without northern pike rarely reach total lengths of more than 40 inches, while muskie in the presence of northern pike occasionally surpass 60 inches
Muskie spawning generally occurs when water temperatures are in the 50’s (oF), and a 40 pound female can produce about 200,000 eggs. Muskie larvae eat plankton after absorption of their yolk sac, and soon switch to a diet of strictly fish. Peak feeding periods for muskellunge usually occur when water temperatures are in the mid-60’s


Photograph of a muskie fingerling. Picture by the Shedd Aquarium, for additional information visit Wisconsin Sea Grant web site.

Muskie Management

The large size and unpredictable nature of muskie have caused their popularity to grow with anglers in recent years. Muskie can reach speeds of near 30 miles per hour in short bursts, but have also earned the reputation of being the fish of “10,000 casts” (Sternberg 1992). Because of their popularity, intensive muskie management programs exist throughout the Midwest and Canada. In Ohio, for example, all inland muskie populations are maintained through yearly stockings of fingerlings. About 10 reservoirs are stocked on an annual basis with fingerlings ranging in size from 8 inches to 13 inches. Such intensive management is crucial due to the lack of spawning habitat in the man-made reservoirs of Ohio. Each spring adult muskellunge are netted from Clear Fork Reservoir by the Ohio Division of Wildlife for collection of eggs and sperm. The resulting larvae are then reared in state hatchery ponds for subsequent stocking. In Ohio, stocking densities of fingerlings usually range from 1 to 2 fish per acre, per year in selected reservoirs. Although intensive management strategies were important in creating and maintaining muskie fishing, the efforts would not have succeeded without the cooperation of anglers. A catch-and-release ethic has developed among muskie anglers, and has resulted in a return rate of more than 90% of caught muskellunge (personal communication, Richard Day, Ohio Division of Wildlife). The muskellunge has developed into a very popular sport fish, and intensive management combined with catch-and-release angling and responsible watershed management will maintain populations for years to come.



Photograph of a 60+ pound muskie caught in Georgian Bay. For additional information visit the Trent University web site.

Article By:
Travis Hartman, Fondriest Environmental, August 2001

References:
Dabrowski, K. D., J. Rinchard, F. Lin, M. A. Garcia-Abiado and D. Schmidt. 2000. Induction of gynogenesis in
muskellunge with irradiated sperm of yellow perch proves diploid muskellunge male homogamety. Journal
of Experimental Zoology 287: 96-105.

Lebeau, B. and G. Pageau. 1989. Comparative urogenital morphology and external sex determination in
muskellunge, Esox masquinongy Mitchill. Canadian Journal of Zoology 67: 1053-1060.

Trautman, M. B. 1981. The fishes of Ohio. The Ohio State University Press, Columbus, Ohio.

Sternberg, D. 1992. Northern pike and muskie. The Hunting and Fishing Library. Cy DeCosse, Incorporated,
Minnetonka, Minnesota.

All web sites referenced have direct hyperlinks to the original source.