Comparison of pair trawling and otter trawling: A preliminary study along the southwest coast of India

Abstract

Though operation of pair trawling is banned, it is operated along the Karnataka coast from August to November. There are no published reports on the specifications of the gear or the modifications that have undergone over the past few years in the region. A comparative analysis of the characteristics of the pair trawls and midwater finfish otter trawls operated along Karnataka coast was carried out. The catch details during a fishing season were collected from both types of trawls. The data pertaining to the gear specifications were collected from the gear fabrication units in Mangalore and Malpe. The length of the head rope (HR) of the pair trawl measured in 2017 was 270m, and the HR of finfish otter trawl was 51m. A 36 per cent increase in the size of the head rope was noticed in case of pair trawls from the year 2015 to 2017. The mouth opening of the pair trawls was between 2.9–4.06 times higher compared to the mid-water finfish otter trawls operating in the region. The trawlers operating along the Karnataka coast undertook both pair trawling as well as otter trawling during the same cruise based on various factors. The catch was significantly higher in the pair trawls compared to the finfish trawls. Hence, the average CPUE worked out to be much higher in pair trawling, which is more than the sum of two individual finfish trawls. The average drag offered by the pair trawls was calculated as 6.74 tonnes at a speed of 3.0 knots, while, it was only 2.28 tonnes for finfish trawls at the same speed. The information collected from the fishermen reveal that the fuel consumption is very high for a pair trawling unit, which may negate some of the profits, but still the overall profit of the unit is high during pair trawling. This entices the fishers to clandestinely undertake pair trawling. Capping of engine power, regulation on the gear size & operation and enforcement of legal mesh sizes should be made obligatory by strict Monitoring, Control and Surveillance mechanisms.