How to Gender Muskie & Pike

Have you ever wondered if the last Muskie or Pike you caught was male or female?

 It’s a common question that everyone has when you’re learning about trophy freshwater fishing. Gendering a Muskie or Pike is quite simple, have them fill out a form!

Sexual differences between Female & Male Muskies

Jokes aside, the simplest way to identify an Esox’s gender is to support and gently turn the fish over. On the underside of the Muskies and Pike is a visible pinkish-red urogenital opening (a.k.a. “vent”) near the anal fin. Male fish have a “key-hole” shaped vent while females have a “pear” shaped vent. Female Esox have larger vents than males to help release BB-sized eggs during spawning.


While the difference is minor, Northern Pike and Muskies have slightly different internal and external urogenital anatomy. In Pike, the genital and urinary ducts open directly to the environment. Whereas, Muskie’s urinary ducts open into a muscular papilla (a nipple-like structure) before releasing into the environment. Regardless, these differences also influence their spawning patterns.  


Spawning Patterns of Muskie


Optimum water temperatures for spawning vary between species. For French River Muskie, males begin to run in May to mid-June when waters reach temperatures around 5.5°C (42°F). Female Muskies run later when waters reach 7.8°C (46°F) and spawn when it hits their preferred range of 9°C ~ 13.5°C (48°F ~ 56°F). Once both genders are united in the French River, Muskies begin depositing their eggs over a wide area in intervals. Typically, a male muskie or several muskies will swim in tandem with the female squeezing themselves against her body and forcing eggs out of her as they cloud the area. Muskies will continue to spawn until the water is 15.5°C (60°F), during which a 40-inch female Muskie can lay upwards of 270,000 eggs.


Spawning Patterns of Northern Pike


As for Northern Pike, they spawn when the ice leaves the French River Provincial Park at temperatures of 4.5°C ~ 7.8°C (40°F ~ 46°F). They also have a different strategy for spawning. Northern Pike concentrates near spawning sites waiting for the proper stimuli such as water temperatures, light levels and the presence of vegetation. Unlike Muskies, which spawn during night hours, Northern Pike spawns during daylight hours with their activity peaking in the afternoon. Pike stays confined to their spawning grounds during the run and will not risk open water to travel between spawning places. However, larger Pike are more active and travel in deeper sections of spawning places than younger Pike who stay in shallower water.




While both Muskies and Pike are very similar to one another, since they’re both members of the Esox genus, there are key differences in their biology and spawning tactics. As another fun fact, research by Dabrowski et al. (2000) discovered female Muskies determine the gender of their offspring, unlike Northern Pike which relies on their male counterpart. This means Pike are similar to human inheritance as males of their respective species can be denoted as XY chromosomal pairing or the Heterogametic sex of the species. For male Muskies, they would be the Homogametic sex of the species denoted as ZZ in a ZW sex-determination system. This is not uncommon for birds, reptiles or even other fish species but shows a rather interesting example of two separate sex-determination systems that can coexist and hybridize with the existence of Tiger Muskies.


For more differences between Muskies and Northern Pike.  


Article by Joe Barefoot, M.B., Outdoor Writer and Nationally Published Author & Photographer




MacClane, A. J., Younger, R. E., & Watkins, F. (1998). Muskellunge & Northern Pike. In McClane’s New Standard Fishing Encyclopedia and International Angling Guide (pp. 646–647 & 693). essay, Gramercy Books.


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.


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.