Diel changes in diet composition of an omnivorous cyprinid - a possible source of error in estimating food consumption.

摘要: Diel changes in diet composition of omnivorous roach (Rutilus rutilus (L.)) and the effects on food consumption estimates given by a bioenergetics model were studied. In all length groups roach, percentage zooplankton diets was higher zoobenthos, plants detritus lower during daytime than night. As result, compared with sampling throughout day, overestimated (by 6–11%) other categories underestimated up to 200%) when only samples taken into account. The error caused diurnal variation larger that 10% deviation digestibility prey energy contents predator prey. results suggest may considerably bias for fish species feed both animal plant material. Additionally, fish-mediated nutrient recycling be biased inaccurate determinations diets.