Temporal changes in the movements and abundance of Thames estuary fish populations
Estuaries play a crucial part in the life cycle of many fish species (Haedrich, 1983) and act as an important nursery area for many marine fish by providing a rich food source and protection from predation (Blaber and Blaber, 1980). The abrupt changes in oxygen concentration, temperature, turbidity, salinity and a number of other factors place considerable physiological demands on an organism. Adaptation to these factors is of course possible (Vernberg and Vernberg, 1976); however, the broad tolerance required to be successful within an estuary limits the number of niches available. Hence, the number of fish species that are truly estuarine is not great. Of the 112 species recorded in the tidal Thames (Appendix B), more than 90 are predominantly marine and only a small number, perhaps 10%, can be regarded as truly estuarine dependent.
KeywordsMigration Sewage Turbidity Bark Sorting
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