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.
Boesemania Boesemania Boesemania is a genus of freshwater fish in the family Sciaenidae. This genus contains the single species Boesemania microlepis. Also known as the boeseman croaker and smallscale croaker, this fish lives in southeast Asian rivers. This is a relatively large species. It can reach in length and in weight. "Boesemania microlepis" lives in Cambodia, Laos, Indonesia (Borneo and Sumatra), Malaysia, Vietnam and Thailand. It is found in several rivers such as the Mekong, Chao Phraya River, Mae Klong, Nan River, Tha Chin River, and Bang Pakong River. This species appears to be sedentary. It prefers large, flowing rivers. During