Gizzard Shad (Dorosoma cepedianum) are schooling filter feeders that eat both phytoplankton and zooplankton.  They only live 3-4 years and can grow up to about 20 inches long.  They have a peak spawn in early spring when water temperatures reach about 70 degrees.  They are not as cold sensitive as their cousins the threadfin shad, but are vulnerable to cold-induced mortality beginning at about 45 degrees.  They can be a valuable forage for Largemouth, Smallmouth, Striped and Hybrid Striped Bass but their rapid growth and large maximum size can make them a liability to a fishery unless they are managed correctly.

We recommend stocking them in large fertilized lakes that are being managed for trophy bass.  Their presence not only results in more bass exhibiting better condition, they lower the harvest requirement for bass from about 25-35 pounds of bass per acre to about 15 pounds of bass per acre.  They are not a panacea for all bass lakes.  They compete with young bluegills for food and tend to decrease the number of bluegills that mature in your lake each year.  They also can change how you fish for your bass and with what lures.  There is a general shift from catching bass here and there at every stump and notable structure to catching them in large numbers in places where they are about to “blow up” on  schools of shad.  Your tackle box begins to hold lots of white and silvery baits that resemble swimming fish.  There is no guarantee when you stock them that they will become “established” in the lake.  We stock a “load” of threadfin shad in the spring before they spawn with the hope that before they all get eaten they will spawn and become established in the lake.  A load is about 25-40 pounds of fish of various sizes (they do not tolerate counting weighing or sorting– they are very fragile and must be transported carefully).  Once established in a lake, we usually recommend a partial rotenone treatment every 3 to 5 years to keep the lake from becoming dominated by large Gizzard Shad.