Threadfin Shad

Dorosoma is Greek for "lance body," referring to the lance-like shape of young shad. The word petenense refers to Lake Peten in the Yucatan, the species type locality. Threadfin shad are usually easily distinguished from gizzard shad by the fact that the upper jaw does not project beyond the lower jaw. The anal fin usually has 20-25 rays, as opposed to 29-35 rays found in gizzard shad. The upper surface is silver-blue and grades to nearly white on the sides and belly. All fins have yellow tint except the dorsal. In this species, unlike gizzard shad, the chin and floor of the mouth is speckled with black pigment.

Angling Importance

Often used as a bait fish. Threadfin shad almost never bite on a hook.

Biology

Like gizzard shad, threadfin shad are most commonly found in large rivers and reservoirs. However, threadfin shad are more likely to be found in waters with a noticeable current and are usually in the upper five feet of water. They are quite temperature sensitive, with die-offs reported at temperatures below 45°F. Spawning begins in the spring when water temperatures reach approximately 70°F, and may continue into the summer. During spawning, one or more females are accompanied by several males. Adults are considerably smaller than gizzard shad adults, rarely exceeding 6 inches in length.

Distribution

Threadfin shad naturally occur in waters west of the Appalachian Mountains, north to Kentucky, west to East Texas, south to the Rio Grande drainage, and east to Florida. The species has been widely introduced in California and Arizona, as well as Appalachian and southern Atlantic states. Threadfin shad are common in all East Texas streams and have been introduced as forage fish in many reservoirs statewide.