长湖达氏鲌的生长特性及其资源现状

2015年9月至2016年8月在湖北长湖采集达氏鲌(Culter dabryi)样本592尾,对其年龄、生长及资源状况进行了研究。结果表明,长湖达氏鲌种群的年龄组成为1~7龄,其中以1~4龄鱼为主,占样本总量的91.38%;达氏鲌属匀速生长类型,其体重(W)和体长(L)的关系式为W=0.008L3.148(n=592,R~2=0.995,P0.01),且无明显性别差异;采用von Bertalanffy生长方程分别拟合体长、体重与年龄的关系,其表达式分别为,体长Lt=49.1031﹣e-0.194(t+0.268)],体重Wt=1668.3301﹣e-0.194(t+0.268)]3.148,生长拐点年龄t=5.64龄,对应体长33.4 cm,体重502.4 g;目前长湖达氏鲌总死亡系数Z=0.80,自然死亡系数M=0.42,捕捞死亡系数F=0.38,资源开发率E=0.48/年,根据体长股分析法估算出长湖达氏鲌2015~2016年资源量为1 809 710尾(15.18 t)。为保持长湖达氏鲌资源稳定,建议捕捞体长33.4 cm以上个体。

Study on the Growth Characteristics and Resource Status of Humpback (Culter dabryi) in Lake Changhu

Humpback (Culter dabryi) which belonging to the genus Culter is a common economical fish which lives in lake and river from south to north in China.The purpose of this study was to clarify population characteristics.We totally collected 592 specimens from Lake Changhu,Hubei Province,in September 2015 to August 2016 and measured the body length and body weight of each individual,collected scales to investigate the marks for each of fish.The results showed that the ring mark on the scales mainly was cutting type and sparse-dense type (Fig.1),there were 7 age classes ranging 1 to 7 in the population,particularly the age classes of fish 1 to 4 years old took advantage in quantity,which accounted for 91.38％ of the total population (Table 1).The standard length of the samples ranged 71 － 388 mm,of 55.07％ of them within the range of 101 － 200 mm;the total weight was with the ranged of 4.0 － 916.2 g,of which 68.75％ individuals weigh in 4.0 － 149.9 g (Fig.2).The relationship between body weight and body length was described by the equation:W ＝ 0.008L3148(n ＝ 592,R2 ＝ 0.995,P ＜ 0.01) (Fig.3).The T test showed that the growth of Humpback belonged to the "constant speed" type;and it was no significant difference between the males and females.According to the growth,the growth rate and acceleration growth rate equation of body length and body weight were described as Lt ＝ 49.1031 －e－0.194(t + 0.268)],Wt ＝ 1668.3301 －e－0.194(t + 0.268)]3.148.The growth inflexion point of the body weight and length was 5.64 years old,and its corresponding body length was 33.4 cm and body weight was 502.4 g (Fig.4).The present mortality coefficient of Humpback is 0.80 (Fig.5),natural death coefficient is 0.42,fishing mortality factor is 0.38,resource exploitation rate E is 0.48 / year.According to the method of body length analysis,the amount resources of the Humpback were estimated to be 1 809 710 individuals (15.18 t) in 2015 － 2016 (Fig.6).In order to maintain the stability of the Humpback resources,it is suggested to catch those fish that is more than 33.4 cm in length.