Tidally influenced river sections are important for many estuarine and migratory fish species, acting as grounds for feeding and spawning, and as nurseries for juveniles. (Image NE)
Tidally influenced river sections
have strong salinity gradients and unique hydraulic regimes governed by the tidal cycle. They are particularly important for a range of estuarine fish and long-distance migratory fish species, either for feeding, spawning and juvenile development or for passage up and down the river. Species using these sections include sea and river lamprey, smelt, flounder, bass, grey mullet, salmon, sea trout, and allis and twaite shads. Marginal tidally exposed muds are important for many invertebrate species and the wading birds that feed upon them. In lowland areas of England tidally influenced river sections been heavily affected by tidal sluices, dredging and flood embankments, which has also resulted in the loss of associated saltmarsh and wider coastal habitat mosaics.