The objective of this study was to evaluate the effect of an introduced predator (saugeye; Stizostedion vitreum X Stizostedion canadense) on the density of intermediate-size white crappie (Pomoxis annularis) and to provide a prey species (threadfin shad; Dorosoma petenense) to facilitate the crappie dietary shift from invertebrates to fish. Concomitant annual stockings of fingerling saugeye and adult threadfin shad were initiated in 1985 and continued through 1991. Although late summer spawns of threadfin shad were documented in 1988 and 1989, trawl samples failed to collect substantial numbers of threadfin shad. Juvenile threadfin densities never exceeded 20% of the maximum gizzard shad (Dorosoma cepedianum) densities for a given year. Threadfin shad did not contribute substantially to the diet of crappie. Stomach analysis of adult saugeye indicated that crappie were a primary component of their diet. Catch rates in trap-net samples indicated a decline in the density of intermediate-sized crappie (130-199 mm) and an increase in catch of crappie ≥200 mm. Crappie growth rates improved, but remained below desired levels. Annual angler harvest of crappie from 1989 through 1991 exceeded the estimated harvest in 3 of the previous 4 years. Recommendations were to continue annual stockings of saugeye but discontinue stockings of threadfin shad. A 457-mm minimum length limit on saugeye was proposed to limit angler harvest of saugeye.
