Rearing maskinonge in a protected area

A method of rearing maskinonge to an advanced fingerling stage was investigated. One hundred thousand fry were planted in a natural habitat; a marshy bay normally used by maskinonge as a spawning ground. An attempt was made throughout the summer to remove all possible fish and turtle predators. Altogether 17,334 coarse fish, exclusive of fry of the year, and 563 turtles were removed from the area. Less than one‐third of the fish and somewhat more than one‐half of the turtles were removed previous to planting the maskinonge fry.

Maskinonge spawn in the spring and the fry remain in the spawning marshes at least until the first of November. The fry show little tendency to range about during the period.

When first commencing to feed maskinonge fry took plankton crustacea and the cladoceran, Polyphemus pcdiculus, was utilized to a large extent. About 1 week later they commenced to take very small minnow fry as well as plankton. After they were about 5 weeks old the diet was composed entirely of fish. Cannibalism did not occur when there was an abundant supply of other food.

Maskinonge grew very rapidly under the conditions provided, reaching an average length of nearly 10 inches by the first of November.

A yield of 0.8 advanced fingerlings for each 1,000 fry planted was obtained. However, since the removal of fingerlings was not completed the yield was probably greater. Many predatory fish, notably yellow perch and rock bass, remained in the area throughout a greater portion of the experimental period. There can be little doubt that their predatory activities reduced the yield.

Advantages of raising maskinonge fingerlings under the conditions described are the abundant natural food supply, making possible excellent growth, and the possibility of eliminating predators to a large extent.