ABSTRACT
Rivers around the world have been consistently exploited and modified to meet human needs. There is evidence for regulation of the Yellow River in China as long ago as 2000 BC, both Roman and Chinese civilizations used weirs and other structures to improve rivers for fisheries, and in the UK, the Domesday Book of 1086 records significant numbers of water mills and river embankments (Brookes 1988; Downs and Gregory 2004). European settlers in the United States and Australia rapidly altered rivers on a large scale. For example, clearing of native vegetation for agriculture in Australia frequently caused transitions in river type (Brierley and Fryirs 2005). In the Unites States, historical accounts of North American fisheries depicted how human settlements and their subsequent effects including dams, mills, boat passage and effluent from towns and cities among others ‘destroy the fisheries of estuaries and rivers far more rapidly than the hook, net, or seine of the fisherman’ (Gesner 1859: 289).
