The Gizzard Shad, a member of the herring family, is native to fresh and salt waters of eastern North America. Its natural range includes the Saint Lawrence River and the Great Lakes and extends west into North Dakota. Gizzard shad are found as far south as eastern Mexico, and as far west as New Mexico. Its range has been greatly expanded through stockings throughout the west. Preferred habitat is sluggish rivers and muddy bottomed lakes, avoiding fast waters. Shad are pelagic and frequently feed near the surface. Gizzard shad are sensitive to sudden changes in temperature and oxygen content, which can cause large-scale, unexpected die-offs.
Gizzards have a deep, oblong body. Free of markings, they are grayish or silvery blue on top transitioning to silver on the sides with a whitish belly. The dorsal fin has a long ray that extends beyond the rest of the fin. The tail fin is deeply forked. Their mouth is inferior, sub-terminal, and toothless. Gizzard shad produce excessive slime and have a noticeable strong “fishy” smell.
Eight to fourteen inches is typical for gizzard shad, but can exceed 18 inches.
Gizzard shad spawn in the spring, when water temperatures rise above 50 degrees Fahrenheit. Diverse habitats are utilized for spawning. Eggs and sperm are broadcast simultaneously near the surface. The eggs sink to the bottom and adhere to submerged objects. Reservoir populations often spawn in creeks tributary to the reservoir. Shad are prolific, producing up to 400,000 eggs.
This schooling, pelagic fish is primarily a plankton feeder. They ingest bottom mud and sand to assist grinding of phytoplankton and zooplankton in their thick walled gizzard like stomachs.
Gizzard Shad in Texas
Dorosoma is Greek for "lance body", referring to the lance-like shape of young shad. The species epithet cepedianum refers to the French naturalist Citoyen Lacepede. Gizzard shad are usually easily distinguished from threadfin shad by the fact that the upper jaw projects well beyond the lower jaw. Amateur ichthyologists can run a finger underneath the mouth forward, and if the fingernail catches on the upper jaw and opens the mouth, in most cases the fish is a gizzard rather than a threadfin shad. The anal fin usually has 29-35 rays, as opposed to 20-25 rays found in threadfin shad. The upper surface is silvery blue, and grades to nearly white on the sides and belly. Fins do not have the yellowing tint present in threadfin shad. Unlike threadfin shad, the chin and floor of the mouth in this species is not speckled with black pigment. Although the species commonly grows to lengths of 9-14 inches, some have been reported to exceed 20 inches in length. In Texas the record (taken with a spear gun) is an 18.25-inch specimen that weighed in at 2.97 pounds.
The species is most often found in large schools. The common name "skipjack" is derived from the fact that individuals within a school may often be observed leaping out of the water or skipping along the surface on their sides. Spawning generally takes place in late spring, usually in shallow protected water. Eggs and milt are released in the school, seemingly without regard for individual mates. Adhesive eggs attach to submerged objects and hatch in about 4 days. Although adult shad are moderately deep-bodied, fry are extremely slender and delicate looking until they reach about 1.25 inches in length. Gizzard shad are planktivorous. Young feed on microscopic animals and plants, as well as small insect larvae. Adults feed by filtering small food items from the water using their long, close-set gill rakes.
Gizzard shad are most abundant in large rivers and reservoirs, avoiding high gradient streams.
In Texas, gizzard shad are found in all major streams and reservoirs.
Gizzard shad provide forage for most game species. They rarely bite on a hook, and when they do, they are generally considered worthless as a food fish. The species is often used as cut bait for other fish species.
Courtesy of Texas Parks and Wildlife