Energy analysis of the stake net operations in vembanad lake, Kerala, India

Abstract

Stake nets are fixed conical bag nets operated in the shallow waters and estuaries where the tidal currents are strong. The mouth of the net is kept open against the current by means of stakes driven to the bottom. Fish production and energy requirement in the traditional stake net operations, in Vembanad lake, Kerala, India are discussed in this paper. Stake nets are primarily targeted at prawns, which drift with the tidal currents. Mean catch per year per stake net was estimated as 0.41 t and mean number of fishing days in a year was 210. Metapenaeus dobsoni formed the dominant component of the catch consisting 92.4%, followed by M. monoceros and Penaeus indicus. Energy inputs in the stake net system has been estimated at 2.13 GJ. Fishing gear and stakes constituted 95% of the gross energy requirement (GER) the balance being contributed by the traditional plank canoe used for carrying the gear and catch. GER was estimated at 5.19 GJ.t fish raised to -1 which was quite high for a stationary passively operated gear. The high GER value of this passively operated, non-motorized gear system is due to the low magnitude of landings by this gear. Energy efficiency ratio obtained was 0.65 and energy intensity value was 1.54.