Impact of man's modifications of river hydrology on the migration of freshwater fishes: A mechanistic perspective
hydrology, migration, streams, energetics, fish biology, ecology
Journal or Book Title
International Journal of Ecohydrology and Hydrobiology
Over the past centuries, rivers and streams across Europe and Northern America have increasingly been modified by damming and by other water regulation schemes. This situation is also becoming increasingly common throughout tropical regions. In the vast majority of cases, such schemes have been developed with little or no consideration to the ichthyofauna, and impacts on biodiversity and fisheries have been and still are numerous. Here we provide an overview of how anthropogenic modifications of river systems, resulting in hydrological changes,also impact on fish migration, focusing on the environmental stimuli triggering or enhancing migratory behaviour, the energetics of migration and their variations between species and lifestyles. This overview concentrates on European freshwater fish species and case studies, but also includes examples from other geographical areas, as the problem tackled here is worldwide.Well-documented long-term case studies of the influences of hydrological changes on fish migration, from the peer-reviewed literature, are still greatly outnumbered by past, present or planned schemes. Additionally, there are many aspects of fish biology, such as spatial ecology, which remain poorly known or understood, yet such knowledge is fundamental to an ecologically sensitive approach to integrated river- and fisheries management.