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Gizzard Shad
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- Oneida Lake individuals may be as long as 19 inches, as heavy as 3 pounds, and be more than 7 years old
- Eat mostly plant material, phytoplankton, and algae
- New York's only true freshwater member of the herring family
Gizzard shad have a distinct appearance with a blunt, rounded snout hanging over a small mouth. They have a long filament on the back end of the dorsal (back) fin, and a row of pointed scales called “scutes” down the belly. Gizzard shad have a deep body that is silver with bluish upper sides and back. A small purple dot appears behind the gill flap, but this disappears during midlife.
Gizzard shad are quiet water fish that live in lakes, bays, and sluggish rivers. They prefer clear water, though they can tolerate high turbidity areas. Gizzard shad are filter feeders, and are one of New York's few freshwater fish that eat mostly plant material, phytoplankton, and algae. To eat, gizzard shad take water or mud into their mouths and then strain it though a set of rakes on their gills. Water and sediment are removed, and the food is captured and eaten. To grind and break up this plant matter, gizzard shad possess a unique muscular stomach called the gizzard.
Gizzard shad spawn during the summer (April-June) in streams and shallow water. Females produce 200,000-400,000 eggs, which sink to the bottom where they stick to anything they come in contact with. Eggs hatch in 2-4 days and the hatchlings feed on zooplankton.
Gizzard shad are not native to Oneida Lake. They were first documented here in the 1950’s, and probably invaded via the canal system that connects Oneida Lake with Lake Ontario. They disappeared shortly after their initial introduction, but were reintroduced through the flooding events that came with Hurricane Agnes. Today, gizzard shad are an important food source for many gamefish and are vital to the walleye here in Oneida Lake. However, gizzard shad are only vulnerable to predation during their early life stages because adults are too large for freshwater predators. If not kept under control, populations can grow rapidly and may become a problem. Along with the unchecked adult population, gizzard shad are not exciting to catch and are not good to eat, leading most anglers to consider them a nuisance species.
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