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
Herring juvenile herring could never catch a large copepod. Other pelagic prey eaten by herring includes fish eggs, larval snails, diatoms by herring larvae below , tintinnids by larvae below , molluscan larvae, menhaden larvae, krill, mysids, smaller fishes, pteropods, annelids, "Calanus" spp., Centropagidae, and "Meganyctiphanes norvegica". Herrings, along with Atlantic cod and sprat, are the most important commercial species to humans in the Baltic Sea. The analysis of the stomach contents of these fish indicate Atlantic cod is the top predator, preying on the herring and sprat. Sprat are competitive with herring for the same food resources. This is evident