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.
Sander (genus) Sander (genus) Sander (formerly known as "Stizostedion") is a genus of fish in the Percidae (perch) family. They are also known as "pike-perch" because of their resemblance to fish in the unrelated Esocidae (pike) family. Local names for the fish have been the basis for many geographical names, like River Suda in Russia or Saunags village on the Baltic coast. The genus includes the following 5 species: Phylogenetic relationships of the species of genus "Sander" based on the concatenated data set of six gene regions and a Bayesian analysis. "Romanichthys valsanicola" is the nearest living relative of the genus "Sander"