Shad - Biology

Biology

Shads are thought to be unique among the fishes in having evolved an ability to detect ultrasound (sound at frequencies above 20 kHz, which is the limit of human hearing). This was first discovered by fisheries biologists studying a type of shad known as blueback herring, and was later verified in laboratory studies of hearing in American shad. This ability is thought to help them avoid dolphins that find prey using echolocation. Alosa are generally pelagic. They are mostly anadromous or semianadromous with the exception of strictly freshwater landlocked species. Alosa are generally migratory and schooling fish. Males will usually mature about a year before females and spawn in the late spring to summer months. Most individuals die shortly after spawning. Alosa are seemingly very adaptive vertebrates and can change readily to adapt to their environment as species are found in a variety of temperatures and waters.