Hawaii Cooperative Fishery Research Unit, University of Hawaii, 2538 The Mall, Edmondson 165A, Honolulu, HI 96822, USA.
J Fish Biol. 2010 Apr;76(6):1343-61. doi: 10.1111/j.1095-8649.2010.02569.x.
Reproduction was investigated in relation to lunar and annual cycles in a population of yellow tang Zebrasoma flavescens, a popular aquarium species commercially harvested in Hawaii. Lunar periodicity was determined to be an inherent characteristic of reproduction; peaks in mean daily egg production, female gonado-somatic index (I(G)) and the fraction of females with eggs were observed at the full moon of each sampled month. An increase in the fraction of late-stage vitellogenic oocytes within the ovaries was also observed at the full moon. Reproductive effort peaked in the late spring and summer as indicated by high values of mean daily egg production, female I(G) and the recorded incidence of females spawning for at least two consecutive days. Mean daily egg production and I(G) of monthly samples were lowest in November to February, although some level of egg production continued throughout the year. Large individual variation in batch fecundity was observed, with a range from 44 to > 24,000 eggs per female produced on a single sampling date. Smaller females, 80-120 mm standard length (L(S)), produced limited numbers of eggs, while females > or = 120 mm L(S) were capable of maximal egg production (> 20,000 eggs per batch). In contrast to trends observed in many fish species, no significant relationship between batch fecundity and adult L(S) > 120 mm was observed in female Z. flavescens. An estimate of annual fecundity (mean +/-S.E. 1,055,628 +/- 120,596 eggs) was also generated using a simple model of the lunar variability in egg production. This study illustrates the importance of accounting for potential variation in egg production over time, especially with respect to diel and lunar cycles, in the design of reproductive studies of multiple-spawning fishes. Greater insight into the environmental factors that regulate reproductive activity may be gained by determining the relative reproductive investment allocated at each spawning event. The ability to estimate annual fecundity for more multiple-spawning species will facilitate examination of the effects of fishing on the reproductive characteristics of these populations and permit examination of life-history evolution across a broader suite of fishes.
在夏威夷商业捕捞的一种受欢迎的水族馆鱼类——黄鳍鲷（Zebrasoma flavescens）种群中，我们研究了与月相和年周期有关的繁殖情况。研究发现，月相周期性是繁殖的固有特征；在每个采样月的满月时，平均日产卵量、雌鱼性腺-体质量指数（I(G)）和产卵雌鱼比例均达到峰值。在满月时，卵巢中晚期卵黄生成卵母细胞的比例也有所增加。繁殖高峰期出现在春末和夏季，表现为平均日产卵量、雌鱼 I(G)和连续产卵至少两天的雌鱼比例高。尽管全年都有一定程度的产卵，但 11 月至 2 月的月样本平均日产卵量和 I(G)最低。在单次采样日期，观察到批量产卵的个体差异很大，范围从 44 到 >24,000 个卵子。体长 80-120 毫米（L(S)）的小型雌鱼产卵数量有限，而体长 >120 毫米的雌鱼则能够实现最大产卵量（每批 >20,000 个卵子）。与许多鱼类观察到的趋势相反，在黄鳍鲷中，批量产卵与成鱼体长 >120 毫米之间没有显著关系。利用产卵月相变化的简单模型，估计了年度产卵量（平均值 +/-标准误差 1,055,628 +/- 120,596 个卵子）。本研究说明了在设计多次产卵鱼类的繁殖研究时，考虑到随时间变化的产卵潜力变化的重要性，特别是昼夜和月相周期的变化。通过确定每次产卵时分配的相对繁殖投资，可以更好地了解调节繁殖活动的环境因素。能够估计更多多次产卵物种的年度产卵量，将有助于检查捕捞对这些种群繁殖特征的影响，并允许在更广泛的鱼类范围内检查生活史进化。
