REU: Role of Oceanic Fronts in the Distribution and Reproductive Strategy of American Eels (Anguilla Rostrata)

美洲和欧洲鳗鱼的产卵区和海洋迁徙线索长期以来一直是个谜。由于年轻的鳗鱼幼虫立即集中在北大西洋亚热带辐合带以南的马尾藻海，因此假设成熟的鳗鱼停止迁徙并在该锋附近产卵，并利用该锋的物理或生物特征来定位。这项研究将直接测试1)成熟的成年美国鳗鱼是集中在额叶区，还是直接集中在额叶区的南部，2)成虫的精细尺度垂直和水平分布与锋面区和邻近水域的特征之间的具体关系。定量水声采样将用于识别适当强度的鳗鱼回声，并绘制其分布模式和密度图。有针对性的中水拖网捕鱼、远程操作的交通工具拍摄的视频、用成熟的圈养鳗鱼作为诱饵的陷阱、以及对卵和新孵化的幼虫进行精细取样，将用于验证目标是否真的是鳗鱼。将利用水声资料、中水拖网捕鱼以及温度和盐度剖面来描述该前沿的生物和物理特征。这项研究将一种生理上独特的远洋洄游鱼类在公海产卵与特定的海洋学特征联系起来。

The spawning area and oceanic migratory cues for American and european eels have long remained enigmatic. Because young eel larvae are concentrated immediately to the south of the North Atlantic Subtropical Convergence in the Sargasso Sea, it is hypothesized that mature eels cease migration and spawn near this front and use physical or biological features of the front for orientation. This research will directly test 1) whether maturing adult American eels are concentrated in, or immediately to the south of, the frontal zone, and 2) how the fine-scale vertical and horizontal distributions of adults are related specifically to characteristics of the frontal zone and adjacent waters. Quantitative hydroacoustic sampling will be used to identify echoes of appropriate strength to be eels, and to map their distributional patterns and densities. Aimed midwater trawling, video from a remotely operated vehicle, traps baited with mature captive eels, and fine-scale sampling of eggs and newly hatched larvae will be used to verify whether targets are actually eels. Hydroacoustic data, midwater trawling, and profiles of temperature and salinity will be used to characterize the biological and physical features of the front. This research links open-ocean spawning of a physiologically unique, long-distance migrating fish to a specific oceanographic feature.