A wintertime net sampling and hydrographic survey was conducted in the Kuroshio Extension (KE) and northern subtropical gyre during 3 cruise-legs in January–March 2006. Conductivity-Temperature-Depth (CTD), expendable CTD (XCTD) and expendable bathythermograph (XBT) surveys were conducted to examine the regional hydrographic structure, which included a distinct KE front water mass boundary, low-salinity subsurface intrusions under and north of the KE current jet, and a deeply mixed anticyclonic recirculation zone south of the current. Large mouth-opening trawl deployments at 36 stations to the north, within and south of the KE collected 1315 leptocephalus larvae, which included ~51 eel and elopomorph fish species. Leptocephali were most abundant/diverse at the southernmost stations at ~25–29°N (29 species), to a lesser extent in the northwestern KE and southern area (27 species), but they were not abundant in the current jet or northernmost areas. Congrid leptocephali were most abundant/diverse (~15 species), with 2 Gnathophis species being most abundant, followed by Ariosoma sp. 7, Ariosoma sp. 4, and Bathycongrus. Smaller numbers of the Nettastomatidae (Saurenchelys stylurus), Muraenidae (12 species), Synaphobranchidae, Chlopsidae (7 species), Nemichthyidae (Nemichthys spp.), Serrivomeridae and a few other families were also collected. Most leptocephali were >50 mm in length for non-mesopelagic eel taxa, because they likely originated from summer–fall spawning and had been transported offshore by the Kuroshio into recirculation areas and farther south possibly by a combination of gyre recirculation and eastward countercurrents. Although the exact transport scenarios of the larvae of the present study cannot be determined, it is possible that some species that spawn along the western margin of the subtropical gyre may use Kuroshio recirculation areas and the wider subtropical gyre as larval development areas by drifting within gyre recirculation before eventually swimming westward to their recruitment areas.

在2006年1月至2006年3月的3条航程中，对黑潮扩展（KE）和北亚热带回旋进行了冬季净采样和水文测量。电导率-温度-深度（CTD），消耗性CTD（XCTD）和消耗性海底热成像仪（XBT） ）进行了调查，以研究区域水文结构，包括明显的KE前沿水体边界，KE射流下方和北部的低盐度地下侵入以及该流以南的深度混合的反气旋再循环带。KE北部，南部和南部36个站点的大型张口拖网渔船收集了1315头小脑le幼虫，其中包括约51种鳗鱼和卵形鱼类。在约25-29°N（29种）的最南端站，小头足类动物数量最多/种类最多，在西北KE和南部地区（27种）的程度较小，但在目前的喷流或最北端的地区它们并不丰富。Congrid leptocephali最丰富/多样（〜15种），其中2种食人鱼种类最丰富，其次是Ariosoma sp。7，Ariosoma sp。4，Bathycongrus。少量的Nettastomatidae（Saurenchelys stylurus），Muraenidae（12种），Synaphobranchidae，Chlopsidae（7种），Nemichthyidae（Nemichthysspp。），蛇形目科（Serrivomeridae）和其他一些家族。对于非近中生鳗类，大多数小脑长超过50毫米，因为它们很可能起源于夏秋的产卵期，并且被黑潮（Kuroshio）运到了再循环区，甚至更南端，可能是回旋再循环和向东逆流的结合。尽管无法确定本研究幼虫的确切运输情况，但可能有一些沿亚热带回旋区西缘产卵的物种可能会通过在回旋区中漂移而将黑潮再循环区和较宽的亚热带回旋区用作幼虫发育区。在最终向西游到其招募区域之前进行了再循环。