STUDY ON THE BI OMASS D ISTRIBUTI ON AND GROW TH PROPERTY OF PARAPENAEOPSIS HARDW ICKII IN THE EAST CHINA SEA

Based on the shrimp survey in the continental shelf of the East China Sea by trawl net from 1986 to 1990 and from 1997 to 2001, 9468 Parapenaeopsis hardwickii were measured, among which 5845 were female and 36-3 male1The survey periods were May, August and November of 1998, February of the following year and survey area was between-6°00′-33°00′N and to the west of 1-7°00′E, there were 115 survey stations1The surveywas synchronously conducted in the northern area (31° 00′-33° 00′ N, 122° 00′-127°00′E), central area (28°00′-31°00′ N, 122°00′-127°00′E) and southern area (26°00′-28° 00′ N, 120° 00′-125°30′E) using the vessel powered with 183187kw and capacity of 100 t1We used a shrimp trawl net,which beam length is-8 m and whose cruise speed is-kn, i1e1, it spent 1h from one station to another1The target of the paper is to describe the biomass distribution and growth property of P1hardwickii, supplemen-ting the scientific information for rational exploitation and fisherymanagement1The results showed that the average capture rate was 45817/g·h, and it had the highest biomass distribution of 99019/g·h in the northern area (31°00′-33°00′N), the following area were in the central sea area (279.1/g·h) and southern area (137.3/g·h) 1From the season var-iation, the peak time in the northern area and central area were observed in the fall season, that is-732.6/g·h and 523.5/g·h, but the off-peak time was in the summer1The peak time in the southern area was observed in the summer (266.6/g·h) while the off-peak time in the spring1The shrimp mainly distributed in the areas between 20 and 60 iso-baths;while in the area to north of 30°00′N, influenced by the Yangtze River diluted water, the distribution reached 127°00′E where the depth is 100 m1The shrimp could survive in the temperature between 10℃ and-4℃ and in the salin-ity of 30-34, so it belongs to eurythermal and euryhaline species1Annually, the number of female were much more than that of male,with its ratio being 1:0.62; the body size of female was bigger than that of male1The annual average length and weight of female were 7116mm, 510g; while for male, they were 5719mm, 213g, respectively1The maximum size and weight appeared in May to July and the minimum ones in September to October1The period from May to Septemberwas its breeding season and the rigorous period was June to July1There were two fast growth periods, one in October to December, and the other in April to July1In the first period, the relative increase rates of female and male were 9.3% 217.5% and 7.9%-13.9%, respectively; in the second period, the numbers were 413%-13.8%, 6.2% 1In conclusion, for making rational use of the stock,moratorium is to be held in the period when body size and weight are small1The stock amount should be increased and replenished so as to enhance the economic benefit and ecological benefit.