The application of fecundity estimates to determine the spawning stock biomass of Irish Sea Nephrops norvegicus (L.) using the annual larval production method
The application of fecundity estimates to determine the spawning stock biomass of Irish Sea Nephrops norvegicus (L.) using the annual larval production method
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DOI：
10.1006/jmsc.2001.1144
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发表时间：
2002-02-01
影响因子：
3.3
通讯作者：
Whitmore, J
中科院分区：
文献类型：
--
作者：
Briggs, RP;Armstrong, MJ;Whitmore, J
通过拖网和纱架收集产卵雌性肾形虫，并在九个月的孵化期内将其保存在单独的容器中，以调查繁殖力方面的情况。捕获后不久在圈养条件下排出卵子的雌性估计平均实现繁殖力为104.3个卵子g（-1）活重（s.e.= 2.7）。通过在一年中不同时间从研究拖网捕获的产卵雌性中取样，估计孵化期间的卵损失为36.7个卵g（-1）（s.e.= 3.3）。通过监测孵化场中的个体获得了类似的值。孵化时的平均有效繁殖力估计为67.6卵g（-1）（s.e.= 4.3)是孵化期间排出的卵数（实现的繁殖力）和卵损失之间的差值。丰富的幼虫在发展阶段I，II和III估计了一系列的调查，使用高速浮游生物采样器。利用温度和阶段持续时间之间的关系，将绝对值转换为日产量值。通过将高斯曲线拟合到调查估计值来估计各阶段的年度幼虫产量。幼虫死亡率（Z = 0.033d（-1）; s.e.= 0.0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 0.006）是使用最大似然法从各阶段的年产量值中估计出来的。以死亡率曲线的截距估计，孵化时的年产量为440 x 10（9）只幼虫（s.e.= 62 x 10（9））。根据1995年爱尔兰海西部成熟雌鱼的年生产量和平均繁殖力估计，其生物量为6290 t（CV = 0.17）。目前国际海洋考察理事会估计，1995年的雌性SSB为7 750吨，从商业渔获量数据分析中获得，在ALP估计的95%置信限内。这表明，目前估计的捕捞死亡率为女性肾在爱尔兰海可能是强大的。
Ovigerous female Nephrops were collected by trawl and creel and maintained in individual containers over the nine-month incubation period to investigate aspects of fecundity. Females which extruded eggs in captivity shortly after capture provided an estimate of mean realised fecundity of 104.3 eggs g(-1) live weight (s.e.=2.7). Egg loss during incubation, estimated by sampling ovigerous females from research trawl hauls at different times of year, was 36.7 eggs g(-1) (s.e.=3.3). A similar value was obtained by monitoring individuals kept in the hatchery. Mean effective fecundity at the time of hatching was estimated as 67.6 eggs g(-1) (s.e.=4.3) and is the difference between the number of eggs extruded (realised fecundity) and egg losses during incubation. The abundance of larvae at development stages I, II, and III was estimated over a series of surveys using high-speed plankton samplers. Abundance values were converted to daily production values using relationships between temperature and stage-duration. Annual larval production by stage was estimated by fitting Gaussian curves to the survey estimates. The mortality rate of larvae (Z=0.033 d(-1); s.e.=0.006) was estimated from the values of annual production by stage, using a maximum likelihood method. Annual production at hatching, estimated as the intercept of the mortality curve, was 440 x 10(9) larvae (s.e.=62 x 10(9)). The biomass of mature female Nephrops in the western Irish Sea in 1995 was estimated from annual larval production and mean fecundity to be 6290 t (CV=0.17). The current ICES estimate of female SSB in 1995 of 7750 t, obtained from analysis of commercial catch data, lies within the 95% confidence limits for the ALP estimate. This indicates that current estimates of fishing mortality for female Nephrops in the Irish Sea may be robust.