Predatory Efficiency of Notonecta Spp. And Percent Survivability of Spawn and Fry of Indian Major Carps

Abstract

The present investigation was conducted in laboratory under controlled conditions of temperature to determine the predatory efficiency of Notonecta spp. (commonly called backswimmers) on Indian Major Carps. Experiment was conducted under two sets of different development stages i.e. spawn and fry of Catla, Rohu and Mrigal with a fix number of Notonecta in triplicates. After fix duration of experiment, spawn and fry were harvested and observed for morphological alterations. The predatory efficiency of Notonecta spp. and percent survivability of spawn and fry of IMC was calculated at the end of experiment. The highest predation rate of Notonecta spp. (2.19) was observed on Mrigal spawn at lowest spawn density, followed by Rohu spawn and lowest predation rate (1.38) was observed on Catla spawn at minimum spawn density. In case of IMC fry, the highest predation rate of Notonecta (2.19) was observed on Mrigal fry at lowest fry density, followed by Rohu fry and lowest predation rate (1.38) was observed on Catla fry at minimum fry density.