Fish diversity in the River Thames

One hundred and twenty species of fish have been identified from the River Thames according to surveys of the river by the Environment Agency (tidal Thames survey 1992-2001 and lower freshwater Thames survey 1995-2001). This diversity includes species of conservation importance, notably sea lamprey, lampern, twaite shad and smelt in the tidal Thames. Non-indigenous fish such as grass carp are now found in the lower river. Sea lamprey appears to have made an annual spawning attempt at Barnes in the upper estuary since 1999. This is the first reported spawning of sea lamprey in the Thames catchment this century. Marine and estuarine species of fish displayed marked seasonal migrations and patterns of distribution. Information acquired in the surveys is being used to inform fisheries management policies.