Alosa to detect ultrasound (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" species are generally pelagic. They are mostly anadromous or semianadromous with the exception of strictly freshwater landlocked species. "Alosa" species are generally migratory and schooling fish. Males usually mature about a year before females; they spawn in the late spring to summer.
Cisco (fish) Cisco (fish) The ciscoes (or "ciscos") are salmonid fish of the genus "Coregonus" that differ from other members of the genus in having upper and lower jaws of approximately equal length and high gill raker counts. These species have been the focus of much study recently, as researchers have sought to determine the relationships among species that appear to have evolved very recently. The term "cisco" is also specifically used of the North American species "Coregonus artedi", also known as lake herring. In previous taxonomic classifications, the ciscoes have been identified as a subgenus "Leucichthys" of the genus "Coregonus". Based