洪泽湖河蚬种群生长方程估算及其应用

Development and Application of Growth Equations for Corbicula fluminea Population in Hongze Lake

2015年4月(春季)、8月(夏季)、11月(秋季)和2016年2月(冬季),对洪泽湖河蚬(Corbicula fluminea)进行了采样调查,共设置30个样点,从各采样点分别随机选取30个河蚬,记录不同壳长、壳宽、壳高和体重的河蚬数量,计算其年龄组成和分布频率,并统计不同壳长组的年龄分布情况,以期为其资源的合理利用与保护提供参考依据。结果显示,形态指标和体重呈现显著的季节变化;壳长、壳宽、壳高、体重和年龄范围分别为1.47~40.82 mm、3.93~27.81 mm、8.46~37.40 mm、0.43~20.56 g和1~5龄,壳长、壳宽、壳高、体重和年龄的优势组分别为15~35 mm(92.6%)、12~20 mm(83.2%)、15~31 mm(88.8%)、2~10 g(79.6%)和2~3龄(76.50%);其相对增长率和生长指标随年龄的增加逐渐降低;壳长-体重关系式为W=1.5×10^(-3)L^(2.5795)(R^2=0.900),Von Bertalanffy壳长和体重生长方程分别为L_t=39.42×[1-e^(-0.33(t+0.6))]和W_t=22.574×[1-e^(-0.33(t+0.6))]~3;拐点年龄为2.73龄,对应的体重和壳长分别为6.69 g和26.28 mm。分析表明,洪泽湖有适宜河蚬生长的环境条件,且秋季为最佳捕捞季节;年龄与壳长和体重显著正相关,可以通过河蚬的壳长和体重来估测其年龄;其生长可分为3个阶段,1~2龄为快速生长期,2~3龄为稳定期,3~5龄为衰老期。建议将拐点年龄所对应的壳长26.28 mm作为洪泽湖河蚬开捕壳长。

To provide a reference for rational utilization and protection of Corbicula fluminea in Hongze Lake,the morphological traits,age structure,growth indices and relative growth rate of C. fluminea in Hongze Lake were analyzed based on an investigation of the C. fluminea population in April（ spring）,August（ summer）,November（ autumn） of 2015,and February（ winter） of 2016. The growth condition of C. fluminea in Hongze Lake was evaluated using growth curve fitting from which growth equations were developed. The investigation was carried out at 30 sampling sites and 30 C. fluminea specimens were collected from each site. The shell length,shell width,shell height（ ± 0. 10 mm） and wet weight（ ± 0. 10 g） of all 900 individuals were measured and ages determined. The specimens were sorted according to shell length,shell width,shell height,wet weight and age. The overall age-frequency distribution and the number and age distribution in different shell length groups was recorded. The morphological parameters and weight of C. fluminea varied significantly with season. The full range and dominant group by shell length,shell width,shell height,wet weight and age were,respectively,1. 47-40. 82 mm（ 92. 6%,15-35 mm）,3. 93-27. 81 mm（ 83. 2%,12-20 mm）,8. 46-37. 40 mm（ 88. 8%,15-31 mm）,0. 43-20. 56 g（ 79. 6%,2-10 g） and 1-5 year（ 76. 5%,2-3 year）. The relative growth rate and growth indices decreased with age. The shell length-wet weight relationship was expressed as： W = 1. 5 × 10-（-3）L-（2. 5795）（ R-2= 0. 900）,and the relationship between shell length（ Lt） and age（ t）,and wet weight（ Wt） and age were described by Von Bertalanffy equations： Lt= 39. 42 ×[1-e-（-0. 33（ t ＋ 0. 6））]and Wt= 22. 574 ×[1-e-（-0. 33（ t ＋ 0. 6））]-3. The growth inflection point for C. fluminea occurred at age 2. 73 yr,at a shell length of 26. 28 mm and wet weight of 6. 69 g. Our study indicates that the environment in Hongze Lake is suitable for the growth of C. fluminea and autumn is the best season for harvesting. There is a significant positive correlation of shell length and wet weight with age,so either can be used to estimate age. The growth of C. fluminea in Hongze Lake can be divided into three stages： rapid growth,1-2 years; stabilization,2-3 years; and senescence,3-5 years. The optimum catchable size of C. fluminea in Hongze Lake is at shell length 26. 28 mm,the approximate growth inflexion age.