ICAR-Central Institute of Fisheries Technology, Kochi and Asian Fisheries Society, Indian Branch
Abstract
Not AvailableBottom trawling is one of the most important fishing methods across the world. In India about 35,230 trawlers of
various sizes are in operation. In the case of trawling, probability of getting catch is directly proportional to swept area and thus to the mouth opening of the trawl. In the present study, we tried to investigate the effect of
speed and warp length on the mouth opening of 27 m bottom trawl, operated onboard research vessel Matsyakumari-II, off Cochin. Trials conducted with six acoustic sensors (Make NOTUS, Canada) two each attached to otterboard and wings, and one each to the head rope and foot rope. Horizontal and vertical mouth opening were recorded for three different warp lengths (60, 70 and 80m) at three different towing speeds viz., 2.9, 3.3 and 3.7 kn. At warp length, 70 m, the mouth opening decreased from 60.66 square meters to 44.26 square meters with increase in speed from 2.9 to 3.3 kn and then increased to 59.26 square meters at 3.7
kn speed. Similar trend was observed for 80 m warp length, where values were 48.13, 36.55 and 51.11 square meters at speed 2.9, 3.3 and 3.7 kn respectively. In the case of 60 m warp length, the mouth opening were 44.23 and 45.55 square meters at 2.9 and 3.3 kn respectively, whereas it further decreased to 31.96 square meters at 3.7 kn towing speed. At 3.7 kn towing speed with 70 and 80 m warp length the opening was maximum.Not Availabl
