Energy Analysis of Mini-trawl Operations, off Cochin, Kerala, India

Abstract

Mini-trawls are towed gear consisting of funnel shaped body of netting closed by a bag or codend and extended sides in the front to form wings. They are usually operated from a single vessel, using a pair of small otter boards as horizontal spreading device. Fish production and energy requirement in the mini-trawl operations, off Cochin, Kerala, India are discussed in this paper. Mini-trawling is generally targeted at coastal prawn resources, particularly Parapenaeopsis stylifera and Metapenaeus dobsoni. Mean catch per year per mini-trawler during the period of study (1997-98) was 10.26 t, 48.1% of which was constituted by prawns, followed by flat fishes (33.1%), crabs (12.0%) and miscellaneous finfishes (6.8%). Total embodied energy inputs into minitrawler operation was estimated to be 207.04 GJ and the energy equivalent of fish produced was 38.62 GJ. The GER t fish^-1for mini-trawling was estimated to be 20.2 GJ, which is quite high for a coastal fishing operation. Kerosene constituted 86.24% of the GER, followed by petrol (8.39%), lubricating oil (3.30%), fishing gear (1.4%), outboard motor (0.58%) and fishing craft (0.06%). Energy ratio for mini-trawling was 0.19 and energy intensity 5.36. The mini-trawl operations in the coastal waters need to be strictly regulated in view of the high GER and predominance juveniles in the landings and the implied negative impacts on environment and resources.