Yu, C., Chen, Z., Chen, L., and He, P. 2007. The rise and fall of electrical shrimp beam trawling in the East China Sea: technology, fishery, and conservation implications. – ICES Journal of Marine Science, 64: 1592–1597. Since the 1980s, shrimp beam trawling has flourished in inshore waters of the East China Sea (ECS) off Zhejiang Province. By 2000, there were more than 10 000 beam trawlers operating in the area. The fishery targets several species of shrimp, including Parapenaeopsis hardwickii, Solenocera crassicornis, Parapenaeus fissuroides, and Trachypenaeus curvirostris. In the early 1990s, electrical beam trawls using pulse generators, powered either from the vessel or from underwater battery packs, became popular in the fishery. As a result of this new technology, the catch rates of shrimp, especially the burrowing shrimp species, increased. At its peak usage, there were more than 3000 vessels using electrical beam trawls in Zhejiang Province and another 500 or more in the adjacent provinces of Jiangsu and Fujian. This technology was also widespread along the Chinese coast, but a lack of regulation resulted in the misuse of electrical pulse parameters that caused damage to juvenile shrimps and other benthic species. In 2001, this fishing method was banned from the waters off Zhejiang Province, and subsequently in other parts of the ECS. This paper reviews the research on electrical beam trawls, the fishery, and fishery-management issues associated with this new technology.

No abstract

No abstract

ABSTRACT., In the design and operation of a trawl net, main theoretical problem is mechanical one such as its configuration and tension. Many scientists have made a lot of hard research on this field. In this paper, the author has described a systematic way for solving the mechanical problem of trawl net, and on some given net, made some initial studies about the hydrodynamic properties of wire-warp and plane PE-web and the calculation of the configuration and tension of wire-warp.Results obtained suggest that the hydrodynamic properties of warp and PE-web made from different materials and forms experimented in tank and their configuration, and tension calculated by solving equilibrium equations.Up to now, the author has not finished the studies on the head rope, food rope and belly webbing of the trawl net. Research work in this respect should be continued.