River Tywi these fish to over in weight. In summer and autumn there is also a substantial run of Atlantic salmon ("Salmo salar"). In May the Tywi has a run of the rare and protected twaite shad ("Alosa fallax") and allis shad ("Alosa alosa"). The Tywi also contains brown trout, eels, pike, and a variety of small fish species, and is home to brook lampreys, river lampreys and sea lampreys. The Tywi has the distinction of having accidentally produced by far the biggest fish ever taken on rod and line in fresh water in Britain. This was a sturgeon ("Acipwienser sturio") weighing
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"