Substratum preferences and diel activity patterns of spined loach Cobitis taenia in England: implications for conservation management.

The substratum preferences of spined loach from eastern England differed significantly between fish of different age groups, sexes, habitat origin (river or drainage ditches) and even between ditches, under experimental conditions. Spined loach from drainage ditches preferred organic sediments, while those from a river showed more variable substratum choice. Significant inter-individual differences were found in river fish, with juveniles preferring sand, while males preferred organic sediment and females gravel. In addition, these preferences often changed at night. A clear pattern of nocturnal behaviour was established. These results have implications for conservation management since the identification of habitat requirements is often based on diurnal distributions.