Abstract The study aimed to determine the annual reproductive cycle of Siganus rivulatusfi females based on monthly variation of the gonadosomatic index (GSI) and histological changes in gonads. A total of 240 fish samples were collected monthly from small-scale (trammel nets) and recreational (angling and pot fishery) fishing from Gökova Bay, the southern Aegean Sea, between July 2017 and June 2018. The length and weight of female fish varied from 10.8 to 26.1 cm with a mean length of 18.7 ± 0.2 cm and from 14.98 to 293.42 g with a mean weight of 91.1 ± 2.93 g. GSI values began to increase in May, peaked in June and gradually decreased in July, indicating that the spawning season was early summer. A total of 240 gonads were histologically examined. Granular, pinkish structure of eggs was observed primarily between April and June, which was consistent with the increase in the gonadosomatic index. Post-spawning follicles were determined in July. Values of the gonadosomatic index gradually decreased after August and they were minimal between September and November. During this period, ovaries were surrounded by immature oocytes at the chromatin and peri-nucleolus stages. These results revealed thatSiganus rivulatusstarted vitellogenesis in April and the gonadosomatic index peaked in June.

中文翻译：

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土耳其爱琴海南部兔鱼 Siganus rivulatus (Forsskal, 1775) 卵巢组织学的初步结果

摘要 本研究旨在根据性腺体指数（GSI）的月变化和性腺组织学变化确定Siganus rivulatusfi雌性的年度生殖周期。2017 年 7 月至 2018 年 6 月期间，从爱琴海南部 Gökova 湾的小规模（筛网）和休闲（垂钓和盆栽渔业）捕鱼中每月收集了 240 条鱼样本。从 10.8 到 26.1 厘米，平均长度为 18.7 ± 0.2 厘米，从 14.98 到 293.42 克，平均重量为 91.1 ± 2.93 克。GSI值从5月开始上升，6月达到峰值，7月逐渐下降，表明产卵期为初夏。总共对 240 个性腺进行了组织学检查。主要在 4 月和 6 月之间观察到卵的颗粒状、粉红色结构，这与性腺体指数的增加是一致的。产卵后的卵泡在 7 月确定。性腺体指数值在 8 月之后逐渐下降，在 9 月和 11 月之间降至最低。在此期间，卵巢在染色质和核仁周阶段被未成熟的卵母细胞包围。这些结果表明，Siganus rivulatus 在 4 月份开始卵黄生成，性腺指数在 6 月份达到顶峰。