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.
Timor Sea were lower. The waters to the east are known as the Arafura Sea. The Timor Sea is adjacent to three substantial inlets on the north Australian coast, the Joseph Bonaparte Gulf, Beagle Gulf and the Van Diemen Gulf. The Australian city of Darwin is the only large city to adjoin the sea. The small town of Wyndham is located on the west arm of Cambridge Gulf, an inlet of Joseph Bonaparte Gulf. Rivers that enter the Timor Sea from the Northern Territory include Fish River, King River, Dry River, Victoria River and the Alligator Rivers. Rivers in the Kimberley region