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.
Herring also found in the Arabian Sea, Indian Ocean, and Bay of Bengal. Herring played a pivotal role in the history of marine fisheries in Europe, and early in the 20th century, their study was fundamental to the evolution of fisheries science. These oily fish also have a long history as an important food fish, and are often salted, smoked, or pickled. A number of different species, most belonging to the family Clupeidae, are commonly referred to as herrings. The origins of the term "herring" is somewhat unclear, though it may derive from the Old High German "heri" meaning a "host,