A gizzard shad is a small fish measuring up to 16 inches (41 cm) on average and weighing up to 3.5 pounds (1.5 kg). Belonging to the herring family, the gizzard shad is blue, silver and gray with a white underside. This species consists of shoaling fish with thin, delicate scales and small, toothless mouths. The gizzard shad is a freshwater fish, usually found in medium to deep rivers, reservoirs and natural lakes.
Larger adult groups of gizzard shad are sometimes found in water with some salt content, such as river mouths and estuaries. This species can tolerate still, sluggish or fast-flowing waters and can tolerate high levels of pollution. Gizzard shad are often found in flood pools. The gizzard shad often thrives in water where other species cannot easily survive, or where pollution in the water inhibits breeding.
The gizzard shad mainly eats algae, insect larvae and microscopic organisms. The flesh of the gizzard shad has an unattractive texture and strong flavor, as well as numerous bones, so it is not terribly popular as a food source for humans. It is most commonly caught to be used as bait for larger, predatory fish such as bass. Classed as a forage food, the gizzard shad is stocked by commercial fish farms as live prey for larger freshwater fish.
This hardy little fish is often sensitive to freezing temperatures. If the habitat is not deep enough, gizzard shad exposed to very cold temperatures too close to the surface often die. While extreme cold can quickly and drastically reduce the number of these fish in a particular body of water, it only takes a small number of surviving fish to repopulate the area, because they breed prolifically. This is commonly seen in regions where temperatures regularly drop below freezing for long periods during the winter. During the spring, when water temperatures begin to rise, huge numbers of young are produced, quickly increasing the numbers and making up for those fish lost during the winter.
During breeding, females eject large numbers of eggs into the middle of a shoal, where they can be fertilized by the males. The gizzard shad does not pick a mate; the eggs are instead fertilized by any random males in the group. The eggs of this species are sticky, and cling to almost any surface.