Frame type double-bag drag net for assessing euphausiasuperba resource

Abstract

The invention discloses a frame type double-bag drag net for assessing euphausiasuperba resource, wherein a polyethylene diamond-mesh netting is adopted; the drag net is characterized in that a single-layer small-mesh four-piece frame structure is adopted; the mesh of the netting at the opening of the net is 50 mm, the perimeter of the opening of the net is 30 meters, and the height of the netting is 2 meters; the opening of the net is sewed on a border rope; the border rope is connected with upper, lower and lateral frames; the length of back and abdominal frames is 4 meters, and the height of the lateral frame is 2 meters; the mesh of the netting on the rear part of the net body is 25 mm, the height of the netting is 2.25 m, the back and abdominal single-piece nettings on the front part are sewed with the two nettings at the rear part respectively, and the lateral net netting on the front part is sewed with the single-piece netting at the rear part; the mesh of the netting of a net bag is 15 mm, the height of the netting of the net bag is 1.2 m, the rear part of the net body is sewed with the front part of the net bag to form two net bags; one floater with buoyancy of 5 kg is arranged on the two sides of the upper frame of the net respectively; an iron chain with gravity force of 10 kg is additionally arranged on the two sides of the lower frame respectively; three cross ropes are adopted by the upper frame; two cross ropes are adopted by the lower frame; and the four cross ropes are crossed and then are connected with one drag rope by using a shackle.

Description

technical field [0001] The invention relates to a trawling gear for marine biological resource investigation. Background technique [0002] At present, the investigation and assessment of fishery resources at home and abroad mainly use acoustic detection combined with trawl verification to comprehensively assess. Trawl fishing gear used for resource verification varies according to the power and main scale of different survey ships. Since most trawl net mouths are mainly flexible cables, the net mouth expansion is uniform under different sea conditions and trawl speed conditions. Not the same, the results of the impact resource investigation and evaluation must be corrected to achieve the accuracy of the evaluation results. [0003] Antarctic krill is one of the marine organisms with the most abundant biomass of a single species in the world, and has broad prospects for development and utilization. my country has never stopped investigating Antarctic krill resources since i...

AI Technical Summary

Problems solved by technology

Due to the renewal of my country's scientific research ships, my country's third-generation polar scientific research ship "Xuelong" has undertaken the research mission since 1995. Compared with the previous polar research ships, the "Xuelong" ship has a large The freeboard is high, but the equipment suitable for trawling operations is simple, and the traditional trawling gear fishing method cannot be carried out normally, which brings a lot of inconvenience to the Antarctic krill trawling survey

For a long time, the "Xuelong" has used IKMT trawling to investigate krill resources. Since its main investigation object is plankton, it is not suitable for follow-up investigations of Antarctic krill resources. The actual effect is not good, and it is impossible to correctly evaluate the Antarctic The abundance of krill resources affects my country's correct understanding and mastery of Antarctic krill resources

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