The spawning area of the Japanese eel is located at the southern part of the West Mariana Ridge in the western North Pacific, but their spawning events have not been observed. To further understand Japanese eel spawning ecology, an interdisciplinary research survey by the R/V NATSUSHIMA (NT14-09, 14 May–4 June 2014) was conducted to detect spawning sites based on the seamount, salinity front, new moon and third quadrant (spawning south of front, west of ridge) hypotheses. Attempts were made to film spawning events with underwater camera systems and to consider if eels might be detected in hydroacoustic observations. Although no Japanese eels or spawning events were video-recorded and no eel aggregations could be clearly identified acoustically, three eggs were collected at two stations in the third quadrant region at or just south of 13° N on 26 and 27 May. Three or four days later, newly hatched preleptocephali were collected at two stations far to the south, including 224 at a station > 160 km southwest of the egg catches, and a few preleptocephali were caught at two stations closer to the egg stations. The eggs and southern preleptocephali were from discrete spawning events, which indicated that at least two spawning sites occurred in May 2014.

日本鳗的产卵区位于北太平洋西部的西马里亚纳海岭的南部，但尚未观察到它们的产卵事件。为了进一步了解日本鳗鱼的产卵生态，R / V进行了跨学科研究调查NATSUSHIMA（NT14-09，2014年5月14日至6月4日）是根据海山，盐度锋，新月和第三象限（产于锋线的南部，山脊的西部）的假设来检测产卵地点的。尝试用水下照相机系统拍摄产卵事件，并考虑是否可以在水声观测中检测到鳗鱼。尽管没有录制日本鳗鱼或产卵事件的声音，也没有声音清晰地识别出鳗鱼聚集，但在5月26日至27日，在北象限或北纬13°以南的第三象限地区的两个站点收集了三个卵。3或4天后，在距离南方较远的两个站点收集了新孵化的小前脑，其中224个位于卵捕获器西南160 km以上的站点，还有几个前小脑被捕获在离卵站点较近的两个站点。