长江天鹅洲故道似鳊年龄、生长和死亡率

摘要

The age,growth and mortality of Pseudobrama simoni were studied using scales of 596 specimens collected in Tian-e-zhou Oxbow from March 2011 to January 2012.It showed that two kinds of annuli were observed in the scales including loose-close and cutting-over pattern.Monthly change in the marginal increment ratio indicated that an annulus formed once in a year,from March to May.The interpretation rate of annual rings reached 97.3％ and the agreement between two times of aging by the same reader reached 85.5％.Observed age ranged from l to 5 year for both seres,and the 1-3 age classes comprised the majority of the sample,accounting for 88.38％ of the total.The growth performances index (p)for female and male of P.simonii was 1.83 and 1.76.The natural mortality and fishing mortality rate was 0.47a-1 and 0.63a-1,respectively.Exploitation rate was 0.57.Our study indicated that the population was suffering from over-exploitation,which need to be well managed.%基于2011年3月至2012年1月采集的596尾似鳊(Pseudobrama simoni)样本,以鳞片为年龄鉴定材料,对长江天鹅洲故道似鳊年龄与生长进行了分析,并依此估算了种群死亡率.鳞片的年轮特征表现为疏密或者切割型；年轮一年形成一个,在3到5月之间形成.鳞片的可判别能力为97.3％,同一鉴定者两次年龄读数间的吻合率为85.5％.渔获物中雌、雄鱼均由1-5个年龄组组成,优势龄组为1-3龄,占88.38％.雌、雄鱼表观生长指数分别为1.83和1.76.种群自然死亡率为0.47 a-1；捕捞死亡率为0.63 a-1;渔业开发率为0.57.天鹅洲故道似鳊种群处于过度开发状态,需合理管理.