厄尔尼诺年春季中国南海中沙群岛海域鸢乌贼的渔业生物学特性

Fisheries biological characteristics of Sthenoteuthis oualaniensis in the spring season in the El Nino year of 2016 in the Zhongsha Islands waters of South China Sea

根据厄尔尼诺年春季(2016年3—5月)我国灯光罩网渔船在中国南海中沙群岛海域生产调查期间采集的572尾鸢乌贼样本,对其渔业生物学特性进行了研究,初步探讨了厄尔尼诺现象对鸢乌贼渔业生物学特性的影响。结果显示,厄尔尼诺年间雌性鸢乌贼胴长范围为59.5~207.5 mm,优势胴长组为90~150 mm,占样本总数的66.24%;雄性胴长范围为56.5~236.5 mm,优势胴长组为60~120 mm,占样本总数的78.81%,雌雄样本优势胴长存在显著性差异。雌性样本体质量范围为7~318 g,优势体质量组为20~140 g,占样本总数的70.18%;雄性体质量范围为7~381 g,优势体质量组为0~80 g,占样本总数的92.14%。雌性鸢乌贼净重比例范围为46.59%~86.67%,平均为70.19%;雄性为42.86%~91.11%,平均为73.12%。不同性别间鸢乌贼胴长与体质量、胴长与净重的生长关系存在显著性差异:雌性胴长与体质量、净重的生长均最适合用幂函数表示,而雄性则均适合用指数函数表示。全部鸢乌贼样本的性别比例为41.43∶58.57,雄性样本多于雌性样本;雌雄样本的性成熟度主要以Ⅰ期和Ⅱ期为主,分别占样本总数的61.7%和85.79%。样本胃饱满度以0~2级为主,胃含物主要包括头足类、中上层鱼类、软体动物以及甲壳动物等。厄尔尼诺年间中沙群岛海域的平均表温较上一年度偏低0.213°C,可能会对该海域鸢乌贼的渔业生物学特性产生影响,使其个体变小。

Based on the 572 samples of Sthenoteuthis oualaniensis collected by light falling-net fishery during March to May in the spring season in the El Nino year of 2016 in the Zhongsha Islands waters of the South China Sea, the fisheries biological characteristics and the influence of El Nino were studied. The result indicated that the mantle length（ML） range was from 59.5 mm to 207.5 mm with a high concentration in 90 mm to 150 mm accounting for about 66.24 percent for females and from 56.5 mm to 236.5 mm with a high concentration in 60 mm to 120 mm accounting for about 78.81 percent for males, respectively. The body weight（BW） ranged from 7 g to318 g with a dominative weight from 20 g to 140 g accounting for about 70.18 percent for females and ranged from 7 g to 381 g with a dominative weight from 0 g to 80 g accounting for about 92.14 percent for males, respectively. The ration of the somatic body weight（SBW） to BW ranged from 46.59 to 86.67 percent with an average of 70.19 percent and from 42.86 to 91.11 percent with an average of 73.12 percent for females and males, respectively. There were significant differences between the BW and SBW growth, and the relationships between the ML to BW and ML to SBW were best described by the power function for females and exponential function for males by the Akaike＇s information criterion（AIC）, respectively. The ratio of females to males was 41.43：58.57, and the samples were most composed of immatue individuals accounting for about 61.7 and 87.79 percent for females and males. The feeding stage was mainly in 0, 1 and 2 grade accounting for 89.42 percent and all of the samples and the food was mainly composed of squids, pelagic fishes, mollusc and crustacean. The result indicated that the average sea surface temperature of the sample waters of the El Nino year of 2016 was 0.213 degrees centigrade lower than the common year of 2015, and the fisheries biological feature of S. oualaniensis was affected by El Nino with a decrease in the body size probably.