4.2 Boat Seine
Boat seine refers to the modified Danish seine named “holbot-holbat”, “liba-liba” in the local term. It is classified as a municipal type when using boats of less than 3 gt, and as a commercial type using boats of more than 3 gt. In shallow waters (10-30 meters deep), the net is operated by an outriggered banca 8-10 meters long and powered by a 110-16 hp engine. Two to four fishermen can operate the gear as the scaring ropes and the tom weight are manually hauled. For deeper waters (30-80 meters deep), the net is operated by a larger outriggered banca 11-15 meters long and powered by an 80-225 hp diesel engine. An improvised winch coupled to the main engine is used to pull the ropes and haul the net. There are 5 to 10 fishermen to operate this gear.
The net design and materials for the small-scale and large-scale Danish seine are similar. Only the size of the net, length of pull ropes and weight of tom weights vary. The method of operation is the same, with the bigger-scale using a winch to pull the ropes and heave the tom weight. Both nets have wings on both sides, the central body and the bag. The most commonly used netting is polyethylene 400d/6-12 and mesh sizes of 25 mm.-60 mm. The scaring rope is usually polypropylene or polyethylene with a diameter of 6 mm-15 mm. and a length of 200-1200 meters for each side. Sinkers and plastic strips are inserted at regular intervals in between the strands of the ropes. The stone or concrete tom weight with two rings, weighs from 50-400 kg. depending on the scale of operation.
The gear is set at the sea bottom to enclose a potential area with demersal and semi-pelagic fish. After determining the depth of the fishing ground and current direction, a buoy marker is released. The banca moves in a semicircular direction while continuously paying out the left scaring rope, left wing, body, bag, right wing and the right scaring rope. On reaching the buoy marker, the end of the right scaring rope is secured. The ends of the left and right scaring ropes are passed through the twin ring tom weight assembly. The tom weight is then dropped into the water and the rings slide through the scare ropes until it reaches the bottom. Immediately, hauling of the ropes starts. This may be done manually or by a winch. As the net wings reach the tom weight, both are hauled until the catch is on deck for sorting. The gear is then arranged for the next operation.
Danish seine fishing is now widely used in bays, coves and gulfs. The simplicity of operation as well as larger-sized and more selective catches will lead to an increase in fishing effort and production in coastal areas.