Physiological and ecological characteristics of diadromous fish in islands of the Pyukyus

普丘斯群岛产鱼的生理和生态特征

• 批准号: 08456100
• 负责人: TAKANO Kazunori
• 金额: $ 3.39万
• 依托单位: University of the Ryukyus
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08456100/
• 关键词: Ryukyu-ayu; Flagtail; Tilapia; reproduction; sea water adaptability; diadromy

This study was carried out to clarify the physiological and ecological characteristics of some selected diadromous fish inhabiting sround the island of the Ryukyus.1.Ryukyu-ayu (Plecoglossus altivelis ryukyuensis) : The structure of mature spermatozoon of this species was characterized by a symmetric nucleus and asymmetric arrangement of two centrioles unlike Ayu, P.altivelis. Scales, comb-like teenth, alimentary canals and skeleton developed earlier than Ayu. Upstream migration also occurred earlier (February-March) and smaller in size (av. 32.3 mm) than Ayu.2.Flagtail (Kuhlia marginata) : Based on the histological observations and gonad-somatic index, it was estimated that females spawn repeatedly during the spawning period from April to September. Number of ovarian eggs varied between 70,000 to 360,000 with an increase of BL.After young migrated from sea to rivers at av. 20mm BL,during March to July, females grew faster than males. The average longevity of female and male was estimated 6 and 2, respectively, and the ratio of female to male resulted in 3 : 1. The change in plasma Na and C1 after trasfer to sea water revealed that the fish have the high ability of tolerance to environmental salinity.3.Tilapia (Oreochromis mossambicus) : The species O.mossambicus is the dominant fish occupying the estuaries of Okinawa Island. The average fertile span of this fish was estimated to be 2-9 years. Annual spawing period lasts from May through September, and females may spawn several times during this season. Although the analysis of the verious physiological parameters such as oxygen consumption rates, plasma constituents and plasma hormone levels under the different salinity conditions showed that sea water may be favorable environment to the fish, they might selsct estuaries as their habitat on the basis of the causes of reproductive strategy of the species.

1.琉球鱼(Plecoglossus Altivelis Ryukyusis)：该物种成熟精子的结构特征是核对称，两个中心粒不对称排列。鳞片，梳状，消化道和骨骼发育早于阿育。上游迁移也发生得更早(2-3月)，规模较小(av.32.3 mm)。根据组织学观察和性腺-体细胞指数，估计雌性在4月至9月的产卵期内重复产卵。卵巢卵数在70,000~360,000个之间变化，卵母细胞数增加。幼虫从海上迁徙到河流后，在av。20mBL3~7月份，雌性生长快于雄性。雌鱼和雄鱼的平均寿命分别为6岁和2岁，雌雄比例为3：1。调入海水后血浆Na和C_1的变化表明，该鱼具有较高的耐盐性。3.罗非鱼(Oreochromis Mossambius)：罗非鱼是占据冲绳岛河口的优势种。据估计，这种鱼的平均繁殖期为2-9年。每年的产卵期从5月持续到9月，雌性在这个季节可能会产卵几次。尽管对不同盐度条件下的耗氧率、血浆成分和血浆激素水平等生理参数的分析表明，海水可能是鱼类的有利环境，但它们可能会根据物种繁殖策略的原因选择河口作为栖息地。

项目成果

Tagawa, M.: "Partial cloning of the hormone-binding domain of the cortisol receptor in tilapla,Oreochomis mossambicus,and changes in the mRNA level during embryonic development" General and Comparative Endocrinology. 108. 132-140 (1997)

Takawa, M.：“莫桑比克罗非鱼皮质醇受体激素结合域的部分克隆，以及胚胎发育过程中 mRNA 水平的变化”普通与比较内分泌学。

Ikehara, S.: "OKINAWA NO SHIZEN O SHIRU". TSUKIJI-SHOTEN,Tokyo, 269 (1997)

池原 S.：“冲绳的 SHIZEN O SHIRU”。

Iwama, G.K.: "Oxygen consumption rates of tilapia in fresh water,sea water,and hypersaline sea water" Journal of Fish Biology. 51. 886-894 (1997)

Iwama, G.K.：“罗非鱼在淡水、海水和高盐度海水中的耗氧率”《鱼类生物学杂志》。

Nakano, K.: "Effect of ambient salinities on carbohydrate metabolism in two species of tilapia Oreochromis mossambicus and O.niloticus" Fisheries Science. 63・3. 338-343 (1997)

Nakano, K.：“环境盐度对两种罗非鱼 Oreochromis mossambicus 和 O.niloticus 碳水化合物代谢的影响”，渔业科学 63・3 (1997)。

Tagawa,M.: "Partial cloning of the hormone-binding domain of the cortisol receptor in tilapia,Oreochomis mossambicus,and changes in the mRNA level during embryonic development" General and Comparative Endocrinology. 108. 132-140 (1997)

Takawa，M.：“罗非鱼、莫桑比克鱼皮质醇受体激素结合域的部分克隆，以及胚胎发育过程中 mRNA 水平的变化”普通与比较内分泌学。