长江中游养殖湖泊大通湖河蚬种群动态及次级生产力

摘要

Samples of Corbiculafluminea (Müller,1774) were collected monthly from March 2011 to February 2012 in the Datong Lake to study its population dynamics and secondary production in its native environment.A total of 4,108 C.fluminea were collected and measured,with shell length (SL) ranging from 3.41 to 29.58 mm,and wet weight (WW) ranged from 0.005 to 10.03 g.The calculated SL-WW equation was log WW=-3.52+3.08 log SL (R2=0.97),which showed that the growth curve of C.fluminea followed a positive allometric pattern.The recruitment patterns peaked in one from March to April and the other one during the months of August to October.The mean annual abundance and biomass ((B)) were (2744-95) ind./m2 and (20.14±5.7) g AFDW/m2 (Ash Free Dry Weight,AFDW),respectively.The annual secondary production (P)was estimated to be 23.90 g AFDW/mLyear,resulting in a P/(B) ratio of 1.20/year and a turnover time of 298 days.The asymptotic maximum length (L∞),curvature parameter (K) and seasonal oscillation in growth rate (C) derived from the von Bertalanffy Seasonal Growth Formula (VBSGF) were 31.91 mm,0.45/year,.and 0.84,respectively.The slowest growth period was in January,and the potential lifespan (tmax) was estimated to be 4.44 years.The total mortality (Z),natural mortality (M) and fishing mortality rates (F) estimateddwere 1.68/year,0.89/year and 0.79/year,respectively.Its exploitation rate (E=0.47) indicated a slightly high exploited stock that needs some management intervention to maintain the sustainability of this fishery resource.%2011年3月至2012年2月,通过逐月调查的方式,分析了大通湖河蚬的种群动态,并采用体长频率分布法计算其次级生产力.调查共采集分析河蚬4108个,壳长(SL)和湿重(WW)范围分别为3.41-29.58 mm和0.005-10.03 g.大通湖河蚬SL和WW之间的关系为WW=-3.52+3.0810gSL(R2=0.97),表明其种群呈异速生长;繁殖高峰主要集中在3-4月和8-10月.河蚬的年平均密度和生物量((B),以无灰干重计,AFDW)分别为(274±95)ind./m2和(20.1±5.7)gAFDW/m2,年次级生产力(P)为23.90g AFDW/(m2.年),P/B系数为1.20/年,周转率为298d.基于VonBertalanffy季节生长方程估算的河蚬生长参数为:渐近壳长L∞=31.91mm,生长速率K=0.45,振幅C=0.84,冬季点WP=0.09,表明大通湖河蚬生长呈明显的季节性,1月生长速率最低.河蚬最长寿命(tmax)约为4.44年,年总死亡系数(Z)为1.68,自然死亡系数(M)为0.89,捕捞死亡系数(F)为0.79,年开发率(E)为0.47.结果表明大通湖河蚬资源处于过度开发状态,急需采取有效的措施对其资源进行合理保护.