Fishing and Gear Technology

11.3.5.Towing speed and duration

Unit 11 - Trawl fishing gear and operation

11.3.Bottom trawling
11.3.5.Towing speed and duration
Towing speed of bottom trawling should be more than the swimming speed of fishes. Usualy fishes will swim at a normal speed of 3-4 times of its body length and will increase the speed up to 7-8 time of its body length per second and fishes will increase further up to 10-11 times of its body length per second when they are in danger known as burst speed which will last for few seconds. For bottom trawling towing speed should be in the range of 1.5-3.0 knots. They again vary with targeted species. For e.g. shrimps and soles 1.5-2.0 for other bottom fishes 2.0-3.5 knots.
Normally towing duration is one hour but commercial trawlers are dragging for 2-4 hours. In order to get good quality fishes one should drag for a short period. If dragging duration is increased fishes will get damaged and deteriorate fast.