Variations in the age and growth of yellowfin tuna larvae,Thunnus albacares, collected about the Mississippi River plume
Variations in the age and growth of yellowfin tuna larvae,Thunnus albacares, collected about the Mississippi River plume
复制标题
密西西比河羽流中收集的黄鳍金枪鱼幼虫（Thunnus albacares）的年龄和生长变化
DOI：
10.1007/bf00005128
复制
发表时间：
1994
影响因子：
1.4
通讯作者：
R. F. Shaw
中科院分区：
文献类型：
--
作者：
Kathy L. Lang;C. Grimes;R. F. Shaw
1987年7月和9月，在墨西哥湾的密西西比河排放羽流附近收集了801条黄鳍金枪鱼幼虫，SL为2.57-7.48 mm。幼虫最丰富的中间盐度（即正面沃茨），叶绿素和大型浮游动物位移值也最高。利用矢状耳石显微结构，我们估计幼虫的年龄范围为3-14 d。这些年龄被用来反向计算产卵日期从7月13日至24日和8月22日至31日。平均绝对个体生长率（体长年龄-1）为0.47 mm d-1，最小二乘线性回归SL = 1.67 + 0.47 AGE（r2= 0.60，Pr> F = 0.0001）代表最佳生长曲线。最高生长发生在接近31%的中间盐度和接近29° C的温度下。在生长上有显著的时间变化，7月采集的幼虫比9月采集的幼虫生长慢（分别为0.37和0.48 mm d-1）。幼虫的综合瞬时日死亡率（Z）估计为0.33 d-1（7月为0.16 d-1，9月为0.41 d-1）。这些结果表明，显着产卵的黄鳍金枪鱼可能会发生在北方墨西哥湾附近的密西西比河排放羽，并建议，幼虫的生长和生存可能会提高羽前沃茨。
Eight hundred and one yellowfin tuna larvae ranging from 2.57–7.48 mm SL were collected near the Mississippi River discharge plume in the Gulf of Mexico during July and September, 1987. Larvae were most abundant at intermediate salinities (i.e. frontal waters) where chlorophyllaand macrozooplankton displacement values were also highest. Using sagittal otolith microstructure, we estimated larval ages ranging from 3–14 d. These ages were used to back calculate spawning dates from 13–24 July and 22–31 August. Mean absolute individual growth rate (length age−1) was 0.47 mm d−1, with the least squares linear regression SL = 1.67 + 0.47 AGE (r2= 0.60, Pr> F = 0.0001) representing the best growth curve. Highest growth occurred at intermediate salinities near 31%, and temperatures near 29° C. There was significant temporal variation in growth, with larvae collected in July growing slower than those from September (0.37 and 0.48 mm d−1, respectively). The pooled instantaneous daily mortality rate (Z) of the larvae was estimated to be 0.33 d−1(0.16 d−1in July and 0.41 d−1in September). These results show that significant spawning of yellowfin tuna may occur in the northern Gulf of Mexico in the vicinity of the Mississippi River discharge plume, and suggest that larval growth and survival may be enhanced in the plume frontal waters.