Hybrid striped bass have been released at two locations in Iowa. The original stocking in 1981 was into Saylorville Reservoir, which was followed each year with plantings of additional sac-fry. Fingerling sized hybrid striped bass were released into Pool 14 of the Mississippi River in 1984, and stocking has continued each autumn.

Since the initial introduction, the Morone hybrids have dispersed widely from Saylorville until they presently inhabit a large segment of the Des Moines River system. Fish have been observed upstream near Ft. Dodge and as far downstream as Ottumwa. Based on these observations, this species will undoubtedly extend its range in the Mississippi River. Abundance of the hybrid depends wholly upon the release of hatchery propagated fish.

Like most hybrids, this fish exhibits taxonomic features of both parent species. It has the deep flat body, small head and the distinct back arch of white bass; yet it maintains the dark gray or blue silvery body coloration and thick dark longitudinal body stripes of the ocean striped bass. Although the hybrid closely resembles white bass and striped bass, it still differs slightly in several features. Two distinctive tooth patches are located near the middle of the tongue. Also, the first stripe below the lateral line is distinct and complete to the tail. Positive identification of hybrid striped bass is considerably easier when viewed alongside purebred parent specimens. There are obvious external differences, but these are not so apparent when viewed alone. From observations in other localities this fish seldom exceeds 10 pounds when fully grown.

Knowledge about hybrid striped bass in Iowa is quite limited since this is a new fish to the region and its life parameters remain under investigation. However, several characteristics are well known. First of all, the most obvious is that hybridization of the parent stock is successful only in the most controlled hatchery conditions. Natural hybridization of the female ocean striped bass and the male white bass or the reciprocal cross is virtually impossible since the two species rarely exist in the same water. In Iowa, this is assured by the fact that striped bass are absent from our waters. Hybrid bass are nearly always monogenetic, which makes secondary hybridization with either parent species virtually impossible. Some mature female hybrids have been collected in the southern United States. Like the white bass, eggs of the hybrid are small in size compared with striped bass. Spawning activity of hybrids has been observed with white bass in one southern location, but no natural reproduction was found.

Hybrid striped bass grow rapidly in Iowa, but like white bass, they are fairly short lived. Three years after the initial stocking of sac-fry in Saylorville Reservoir, specimens of 20 inches in length and 5 pounds in weight were reported by fishermen. The record hybrid caught in the Des Moines River below Red Rock Reservoir in 1985 weighed 8 pounds, 3 ounces.

The hybrid striped bass, like its parent stock, is carnivorous, feeding voraciously on schools of gizzard shad. It is also known to forage for silversides, sunfish, insects and crustaceans.

*Mayhew, J. (editor). 1987. Iowa Fish and Fishing. Iowa Department of Natural Resources, Des Moines, Iowa. 323 pp.