AN ECOLOGICAL STUDY ON CLUPANODON PUNCTATUS IN THE WATERS OF DONGSHAN ISLAND
Lu Zhenbin; Dai Quanshui; Yan Youming (Fujtan PrOvincial Institute of Fisheries Research, Xiamen, China, 361012)
A study was made on the distribution and seasonal variation in biomass and density, the characteristics in growth and death, and the behaviors in feeding and reporduction of Clu-panodon punctatus in the waters of Dongshan Island, Fujian Province. it was found to have a monthly mean biomass of 222. 21 kg/km2, representing 27. 22% of the monthly total biomass of necton in that area and making it become a dominant species. its biomass and density were found to be lowest in spring but highest in winter(524. 9 kg/m2 and 9332 Ind/km2,re-spectively), i. e.,they in winter being 23. 77 times and 87. 21 times, respectively, those in spring. The horizontal distributions of biomass and density had obvious regional variation. They were 438. 2 kg/km2 and 7405 ind/km2, respectively,inside the Dongshan Bay that were 78. 71 times and 69. 38 times, respectively,those outside the Bay. the caught fish population consisted of 5 age classes (0～IV ),with class I being dominant. The fork length of the fish population ranged from 111～223 mm, with 141～160 mm being predominant. The living food organisms included mostly Nitzshohia, Thalassionema, Coscinodiscus, Melosira and Skele-tonema Of Bacillariophyta, in addition to a large amount of organic detritus ingested. The first minimum age for sex maturity was class I. The minimum fork length was 140 mm for male and 146 mm for female. The matured female and male were largely in 151 to 170 mm group. From winter to early spring was the main spawning period. The parameters of growth were: L∞ = 246. 37 mm, W∞= 182. 65 g, k= 0. 4303, to= 0.8649, the age of the turnning point of body weight growth was 1. 6017 year(tr). The instantaneous rates of total mortality,natu-ral mortalily and fishing mortality were found to be 1. 2016, 0. 7702 and 0. 4314. The rate of development was 0. 3590. There remains much potential for expoitation.
【CateGory Index】： S917