Otolith elemental analyses for migration history of fishes

1.本研究利用耳石显微结构和微量化学（Sr：Ca比值），对采自三重县宫川河口附近沿岸沃茨的仔稚鱼和采自岐阜县宫川和长良川的成鱼的年龄、出生日期和迁移历史进行了研究。漂入海后，在未长到20 mm长时，其分布由沿岸转移到碎波带。当它们达到30- 40 mm时，在河口出现，然后开始向上游迁移。较早出生和较大尺寸的青少年往往去上游在春天早些时候。此外，出生较早，并经历了上游迁移的鱼在较大的规模表现出产卵早，规模大的趋势。此外，还对分布于三重县铫子川最下游的“盐香鱼”进行了碳、氮稳定同位素组成的测定，确定其分布于三重县长子川最下游， ...更多信息 艾德在河口产卵，以河口附着的藻类为主要食物。2.日本鳗鲡的洄游利用日本种岛玻璃鳗鲡的耳石氧同位素组成测定其产卵温度和深度。耳石芯的氧同位素组成与邻近海域的耳石氧同位素组成无明显差异，表明其产卵温度为12-28℃，产卵深度为320-50 m。对和歌山县伊势湾和串本的玻璃鳗进行了耳石显微结构和微量化学（Sr：Ca比值）分析，结果表明，玻璃鳗的沿海洄游持续时间为20-24 d。从抵达沿海沃茨到补充的时间估计为9至12天。两个采样点的玻璃鳗在这些持续时间上没有差异。建议玻璃鳗鱼直接迁移到每个。3.海鳗的洄游与变态对采自三重县伊势湾、滨岛和茨木县大洗的海鳗幼体进行了耳石显微结构和微量化学（Sr：Ca比值）的研究。从三个采样点收集的幼虫在招募和变态开始时的年龄没有差异。经3个月的远洋洄游后，经1个月的沿海洄游，开始变态。变态开始后60-80天，随着胃功能的建立，器官分化完成。少

1.Distribution and migration of Ayu.Age, birthdate, and migration history were examined for larvae and juveniles collected from coastal waters around the mouth of Miya river, Mie prefecture, and for adult fish from Miya river and Nagara river, Gifu Prefecture, using otolith microstructure and microchemistry (Sr : Ca ratio). After drifting into the sea, the larvae shifted the distribution from the coastal areas to the surf zone before they grew to 20 mm long. They subsequently occurred in the estuary after they reached 30-40mm, and then began their upstream migration. The earlier born and larger size juveniles tended to go upstream earlier in the spring. Furthermore, fish that were born earlier and underwent the upstream migration earlier at a larger size showed a tendency to spawn earlier and larger size. We also examined carbon and nitrogen stable isotopic compositions of "Shio-ayu" which distributes in the lowest reach in Choshi river, Mie Prefecture, and determined that it distribut … More ed in estuary and feed on estuarine attached algae as a major food.2.Migration of the Japanese eel.Otolith oxygen isotopic composition of glass eels collected from Tanegashima Island, Japan, was examined for determining the spawning temperature and depth. The oxygen isotopic composition of the otolith core was not different from those of otolith neighboring region deposited during leptocephalus stage, suggesting that the spawning temperature and depth were 12-28℃ and 320-50 m in the water column, respectively. Otolith microstructure and microchemistry (Sr : Ca ratio) of glass eels recruited in Ise bay and Kushimoto, Wakayama Prefecture, suggested that the duration of coastal migration was 20-24 days. The duration between the arrival at coastal waters and recruitment was estimated to 9-12 days. There was no difference in those durations among glass eels from the two sampling sites. The glass eels were suggested to migrate directly to each. river they recruited after they detrained from the Kuroshio.3.Migration and metamorphosis of Conger eel.Otolith microstructure and microchemistry (Sr : Ca ratio) of conger eel larvae collected from Ise bay and Hamashima, Mie Prefecture, and Oarai, Ibaraki Prefecture, were examined. There was no difference in ages at recruitment and at beginning of metamorphosis among the larvae collected from three sampling sites. They were found to undergo one month coastal migration with beginning of metamorphosis, after 3 month oceanic migration. Organ differentiation was completed for 60-80 days after the beginning of metamorphosis with the functional establishment of stomach. Less