8.2   Fish Liftnets

             The group is the most advanced and diverse type of liftnet. They have many peculiar techniques and methods of operations which vary between types of boats and fishing areas.

            The simplest is the liftnet for small pelagics, and uses a small outriggered, motorized, banca. The size of the net depends on the length of the boat, outriggers and length of the extension booms. The mesh size depends on the target fish.

             A unique method of operation is the small-scale bagnet of Zambales, locally termed “singapong”. The net is 10.8 meters long by 9 meters wide and 4.2 meters deep. It is made of nylon multifilament 210d/4 with 8 mm. mesh size. The wooden outriggered banca has a length of 8-10 meters, powered by a 10-16 hp gasoline engine. It is usually manned by two fishermen.

              Upon arrival in the fishing ground at dusk, the banca is anchored and starts lighting using two kerosene lamps, of 500 watts each (petromax). When sufficient fish schools are attracted, the lamps are transferred to a bamboo float with a 20-m retrieving line which is allowed to drift for some distance from the banca. The fishermen prepare four bamboo poles, 7 meters long, with a base diameter of 6-8 cm. and the end portion diameter is 3-4 cm. The pull ropes are passed through the pulleys which are tied at the end of the bamboo poles. The net is lowered beneath the banca while simultaneously retrieving the floating lamps into their original position. A conical-shaped covering is placed around the lamp to concentrate the fish school. At a given signal, the fishermen start hauling the net until the catch is brought on board. Operations may be done 3 to 5 times per night. Major species caught are anchovy, scad, sardine and small caesio.

              The other type of liftnet uses eight booms to spread the net. The eight booms are supported by ropes which are connected to one or three masts of the boat. A manual winch is provided at the center of the boat to facilitate hauling of the pull ropes. In some fishing grounds, lights (200-1,000 watts/bulb) are only placed in the bow but the majority of the lights are distributed around the boat. Ten to twenty bulbs are used depending on the size of the boat and power of the generating set.

               The latest development in fish liftnet fishing is the provision of 10-20 halogen lights from 1,000-5,000 watts per bulb. Underwater metal halide lights are also being used to attract deeper swimming fish to come to the surface.

              The biggest fish liftnets are found in Cavite , Quezon, Davao , and Zamboanga. The outriggered boat measures 25-30 meters long by 3-4 meters wide and has 2-3 meters draft. Commonly used engines range from 80-220 hp with a generator of 10-24 KVA. The boats have one or three masts along the center part to support the extension booms during operations. They are provided with 19x1,000 watt bulbs or 2-8 units of high wattage metal halide bulbs of 1,000-5,000 watts. The net measures from 20-40 meters long by 15-20 meters wide and is 8-15 meters deep.

                Lighting is the method of fish attraction. At dusk, all lights are turned-on until a sufficient fish school has been attracted. The lights are then turned-off one by one until one light remains. A conical shaped cover is placed on the light to concentrate the fish school. The net is then lowered and remains on the bottom for some minutes. After the fish school is concentrated at the center of the net, the fishermen start pulling the pull ropes until the net is hauled on board. The catch is poured on deck for sorting and storage. The light are again turned-on for the next operation.

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