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
Columbia River supports several species of anadromous fish that migrate between the Pacific Ocean and fresh water tributaries of the river. Sockeye salmon, Coho and Chinook (also known as "king") salmon, and steelhead, all of the genus "Oncorhynchus", are ocean fish that migrate up the rivers at the end of their life cycles to spawn. White sturgeon, which take 15 to 25 years to mature, typically migrate between the ocean and the upstream habitat several times during their lives. Salmon populations declined dramatically after the establishment of canneries in 1867. In 1879 it was reported that 545,450 salmon, with an average weight