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 Hook River Fish Hook River The Fish Hook River, also spelled Fishhook River, is a tributary of the Shell River, long, in north-central Minnesota in the United States. The river's source, Fish Hook Lake, collects short tributaries known as the Portage River and the Potato River. Via the Shell and Crow Wing rivers, the Fish Hook River is part of the watershed of the Mississippi River. The river flows for its entire length in southwestern Hubbard County; its watershed extends into northeastern Becker County. Its name is a translation of the Ojibwe name for the river and Fish Hook Lake, "Pugidabani". The