Sperm production and success of natural fertilization were examined for both muskellunge and northern pike to assess their potential importance in natural reproduction. The annual cycle of spermatogenesis, the relative sizes of the testes and the production of spermatozoa were determined for both species. Mature testes in muskellunge weigh less than half those of northern pike of the same size. The density of spermatozoa within the testes of muskellunge was about 7% less than for northern pike.
The viability of naturally spawned eggs of both species was determined by collecting eggs with trays and handnets in 1960 and 1964. Fertilization rates of 47.2% and 70.6% were determined for two collections of northern pike eggs on trays. Fertilization rates of newly spawned muskellunge eggs ranged from 30.0% to 88.4% for three tray collections. Slightly less than 50% of these eggs remained alive after 3-4 days laboratory incubation in aerated water. The viability of eggs collected with hand nets from Anacharis beds was low. Predation by minnows caused significant egg mortality at one site.