Vol. 11, Special Issue 4 (2022)

Author(s):
Shaik Kouser, Subhasis Dolui, NA Talwar, Gora Shiva Prasad, Satyanarayana Boda and Manjusha Vutukuri

Abstract:
In the present study a conical dip net with a wide circular mouth of 0.85 m and a narrow cod end of 0.35 m made of uniform mesh of 2.8 cm (knot to knot) of multifilament nylon twine no 4, fitted with electrodes to energize the net, was used. Three sets of positive and negative electrodes (stainless steel sphere with 14 gauge bare copper wire; aluminium ring containing 8 droppers with 14 gauge bare copper wire and aluminium conduit coil with aluminium conduit hemisphere, as positive and negative electrode respectively) were used in the present study. Nine species of common Indian freshwater fishes were experimented during the study. The objective was to stimulate fishes, in and around the electrode to attract them centrally near the positive electrode for capture. A total of 16 sets of trails with electrified dip net and non-electrified dip net were conducted in a glass tank of 1.8 × 1.05 m dimension having a water depth of 0.52 m, having a water temperature of 22 to 31 ˚C and electrical resistance of 5000 to 6700 ohms/cm². The results revealed the superiority of electrified dip net over the conventional non-electrified net. Among nine species L. rohita followed by N. Notopterus, C. punctatus, H. fossilis, and C. mrigala was more prone towards the electrified dip net. Fishes of all varieties above 150 mm length could be easily influenced towards the electrified dip net.