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.
Fish River (Alaska) Fish River (Alaska) The Fish River is a waterway in the U.S. state of Alaska. The river rises in the Bendeleben Mountains and flows south to Golovnin Lagoon, before emptying into Golovnin Bay, Norton Sound, and the Bering Sea. The basin formed by the Fish River is known for its placer gold deposits, and in particular, the Niukluk River and its tributaries; production from this tributary valley is reported to be more than from any other place in the region. A galena mine existed from the sea, worked on occasion by a San Francisco corporation with a few hundred tons