In recent years, the traditional large marine fish and shrimp resources have been seriously damaged due and failure, fish and shrimp resources are relatively small rise. Bohai Sea and the Yellow Sea coastal resources of small fish and shrimp species, especially among very rich reserves mantis shrimp, if mantis shrimp trawl conduct production, will damage the young fish. Now mantis shrimp gillnet fishing techniques are described below.
First, the nets structure
Principal dimensions: 75.6 × 7.18 m
1, the main netting: Nylon 6 monofilament, 0.25 mm, 30 mm mesh large, double knot, Zongmu use, each piece netting long 4000 mesh, 290 mesh high.
2, the margin of netting: the upper edge network using twisted Polyethylene 36 special 2 × 3, the mesh is 60 mm, double knot, length 2000 mesh, mesh high 4; the lower edge of the network using twisted Polyethylene special 3 × 3 of 36 line, mesh large 60 mm, double knot, long 2000 mesh, high 5 orders.
(II) The cable stays
1, the floating line: Polyethylene rope, specifications for the 36 special 60 × 3, s, z twist each one, each 76.1 meters long, part ligation netting 75.6 meters long.
2, sinker Gang: Polyethylene rope, specifications for the 36 special 120 × 3, s, z twist each one, each 76.1 meters long, 75.6 meters long ligation netting section.
3, the buoy rope: Polyethylene rope, specifications for 36 special 210 × 3, 30 meters long, 15-25 pieces per boat.
4, the side Gang: Polyethylene rope, specifications for 36 special 120 × 3, s twist, 7.72 meters long, 7.18 meters tie network part, 2.
5, bridle: Polyethylene rope, specifications for the 36 special 180 × 3, z twist, 22 meters long (10.7 meters long on the bridle, the bridle under 11.3 m long, 2.
6, anchor Gang: Polyethylene rope, s twist, specifications for the 36 special 360 × 3, 25 meters long, 16-26 pieces per boat.
(C) float, sinker and other
1. Float: hard plastic float ball, diameter 80 mm, each 52-55 grams dry weight, buoyancy 150 grams per piece net 76.
2, sinker: intermediate ceramic, ellipsoid, the long axis of a hole, the dry weight of 125 grams each, each network 180.
3, buoy: aquaculture spherical plastic float, 15-25.
Second, gear assembly
1, the float, sinker penetrate a float, the sinker Gang, another float, the inner edge of the mesh network edge sinker steel penetration, then two float, sinker Gang tie knot together, every 26.5 cm a tie, each 7 orders, bar 285, left 5 orders were placed at both ends (at each end of the outer 2.5 mesh). Hanging ratio of 0.63. Float spacing 1.008 m, 0.422 m spacing sinker.
2, will float, sinker Gang outer end portion extending netting made eye ring and bridle connection.
3, the two sides were wearing gang clothing side edges within a mesh network, connecting floating line, sinker Gang lower connection.
4, mesh fork rope linked in sequence, with the anchor rope connected nodes. Each anchor weight of about 20 kg.
135 hp mantis shrimp fishing can be carried out gillnet operations, crew 4-8, with net at 15-25.
Fourth, the fishing method
1, put the net:
At high tide, the outermost end of the first network anchor thrown, boats cross flow micro-speed forward, along the flow of nets, top flow cast anchor, anchor pitch ratio gear reduction and bridle knot length and short length of about 10 meters.
2, from the network:
Advection from the net before the turn out from the shore. When hauling, general ship overhead stream, hull and net column vertical, one person operating the boat, a man with a hauling machine twist buoy ropes and sinker Gang, one or more pull floating line and netting, while pulling the network side pick mantis shrimp . Up flow work is good, down stream of bad jobs.
Fifth, the fishing season
Fishing season in late March to mid-May, mid-September to early November, Wang Xun each period in a month or so, the highest net yield over 1000 kg, generally net yield 750 kg.
Mantis shrimp gillnet fixed by the anchors, fishing inshore, simple operation, energy saving, high efficiency, can be used concurrently, crop rotation tool with a wide range of value promotion.