Detritus Settlement Rates in Carp Culture Ponds

The detritus sedimentation rates in nursery, rearing and stocking ponds of a freshwater fish farm in India were quantified using detritus traps (1.4 cm diam). The mean ranges of detritus settlement at the surface level in nursery, re ring and stocking ponds (mg/cm2/d) were 0.27-2.70, 1.94-7.03 and 1.76-4.09, respectively, and the corresponding ranges at the bottom were 0.45-10.31, 3.58-15.89 and 21.45-9.94 mg/cm2/d. The mean levels of detritus in the three types of ponds were 14.46, 24.70 and 13.10 g/m3. Though its caloric content was low (0.25 kcal/g dry weight), considering the quantum of plankton in a similar volume (0.17-0.30 g/m3), the trophic contribution of the detritus in carp culture ponds (3.28-6.18 kcal/m3) was significant. This demonstrated the potentials of detritus in sustaining the heterotrophic food chain and coprophagy in these systems as also the possibilities of its enrichment to improve the production efficiencies.