Gizzard shad were illegally introduced into Claytor Lake, Virginia in the late 1980s; this study evaluates their impact on piscivorous sportfishes. We collected piscivores (stocked striped and hybrid striped bass, walleye, and three black bass species) by electrofishing and gillnetting over a 2-yr period (October 1996-September 1998) to describe their seasonal diets and annual growth rates. Age-0 gizzard shad were eaten even by the largest sportfish to the near exclusion of older aged shad. The moronid species most heavily utilized gizzard shad as forage (as much as 65% by weight of stomach contents) especially in late Summer and Fall. During the first Summer, gizzard shad represented only 7% of moronid species diet composition compared to > 50% in the second Summer. The walleye diet included > 30% shad in Fall, 20% in the second summer, but < 5% during the first Summer and Spring. Shad constituted > 20% by weight of largemouth bass diets the first Spring, but < 10% for all three black basses the remainder of the study. A weak 1997 gizzard shad year class followed by a stronger 1998 year class helps explain discrepancies observed gizzard shad utilization between years. Striped bass annual growth rates have improved a average of 12% for ages 1-5 since pre shad years. Walleye growth rates for ages 1 and 2 have improved 25% and 8%, respectively, while black bass growth has declined an average of nearly 20% for ages 1-4.