6.2 Drift Gill Net
The nomenclature of drift gill net depends on the targeted species. The common species are mackerel, flying fish, tuna and tuna-like, manta ray and other pelagic species. These fish species require different mesh and twine sizes as well as material to maximize catches.
For mackerel, flying fish, sardines and other small pelagic species the nets are made of Nylon monofilament of 0.20 mm to 0.40 mm diameter with mesh size from 25 mm to 90 mm The net consisting of several units is set in known areas of the target species. It drifts with the current for 3-6 hours and is then hauled manually. Another technique in setting is the drifting of the net with the banca where a light marker is placed at one end. Another innovation in Cagayan is a combination of drift gill net and hook and lines which are tied at the center of the net at regular intervals to maximize the catch. The method, however, has some problem whenever current and waves are strong and entangle the fishing gear.
For tuna species, the material is Nylon multifilament PA 210/12 to 210/18 in the main webbing whole iron rings and/or thicker multifilament nettings (210/30 to 210/36) are used as weights. The mesh size ranges from 50 mm to 90 mm There are 10 to 20 meshes of thicker netting acting as weights in the lower portion of the webbing. The net may be set or drifted with the current or tied to the banca during operations. Tuna drift gill nets are popular on the Ilocos Coast, in the Davao Gulf, the western waters of Batangas and the southern waters of Negros Oriental.
One peculiar type of drift gill net is used in the catching of the Manta ray in Jagna, Bohol. The net is made of polyethylene No. 4 (2 mm) with 650 mm mesh size. The net consists of different colors (green, yellow and black) with corresponding numbers of meshes. The depth of the net is around 30 m. It has 2.5 m long suspension lines, to enable the net to stay at mid-water depth. It also drifts with the current, when setting at day or night time. The species command a high price which encourages fishermen to locate good fishing grounds. Compared to the lower hanging rate of tuna and small pelagics nets, the hanging rate (0.85) of the Manta ray gill net is very high when the netting is almost fully stretched. An iron gaff hook is also ready for a big catch.