Although juvenile anguillid eels live in freshwater/estuarine habitats, and marine eels live in diverse ocean environments ranging from shallow-to-deep continental shelf areas and around islands to deep-benthic habitats and deeper meso- and bathy- pelagic zones, the larvae (leptocephali) of all species mix together in the ocean surface layer. All types of eel habitats are present in the western South Pacific (WSP), so it is a unique region for studying long-lived leptocephali, especially because the westward flowing South Equatorial Current (SEC) and several countercurrents pass through many different WSP island groups and deep waters where both anguillid and marine eels live and spawn. Large mouth-opening IKMT sampling surveys for leptocephali were conducted in the southwest Pacific extending to French Polynesia in Jan-Mar 2013 (99 tows, 78 stations, 1052 larvae) and Jul-Sept 2016 (187 tows, 111 stations, 3976 larvae) that collected about 152 species of 18 anguilliform and elopomorph families. The larvae of mesopelagic serrivomerid eels were the most abundant taxa in all oceanic areas, and they were particularly abundant at northern SEC or equatorial latitudes. Australian and New Zealand anguillid eels had spawned in the western SEC areas, as previously detected, and the larvae of tropical anguillids were also only caught in western areas. The larvae of the mesopelagic nemichthyid and derichthyid eels were also widely distributed at lower abundances and with more patchy distributions, but larvae of Eurypharyngidae, Cyematidae, and Monognathidae were rare. Shallow-water eel larvae were most abundant west of New Caledonia near the banks of the Chesterfield Islands, or near other island-groups, but they were rare in the 2 easternmost 2016 transects passing by both sides of Tahiti. Some conger eels were suggested to have spawned in offshore areas in the western region. Congrid Ariosoma and various shallow-water or slope eels had spawned in the region near the Chesterfield Islands or near New Caledonia where current jets can transport larvae westward, and eastward countercurrents exist. Some taxa of larvae of coastal species (muraenesocids, and elopomorphs) were extremely rare, all non-mesopelagic eel larvae were rare in the far-eastern transects, but the New Caledonia region with large shelf areas appears to be a high biodiversity region for marine eels, as it is for reef/shore fish in general.

虽然幼年鳗鲡生活在淡水/河口栖息地，而海鳗生活在不同的海洋环境中，从浅到深的大陆架区域和岛屿周围到深底栖地和更深的中上层和深海带，但幼体 ( leptocephali) 所有物种在海洋表层混合在一起。所有类型的鳗鱼栖息地都存在于南太平洋西部（WSP），因此它是研究长寿细头鱼的独特区域，特别是因为向西流动的南赤道洋流（SEC）和几个逆流穿过许多不同的 WSP 岛群以及鳗鲡和海鳗生活和产卵的深水区。2013 年 1 月至 3 月，在延伸至法属波利尼西亚的西南太平洋进行了大型开口 IKMT 细头动物抽样调查（99 条，78 个站，1052 只幼虫）和 2016 年 7 月至 9 月（187 条，111 个站，3976 只幼虫）收集了 18 个鳗形科和 elopomorph 科的约 152 种。中层海鳗的幼虫是所有海洋区域中最丰富的分类群，它们在北SEC或赤道纬度特别丰富。如先前所发现的，澳大利亚和新西兰鳗鲡在 SEC 西部地区产卵，热带鳗鲡的幼虫也仅在西部地区捕获。中层海鳝和鳝鱼的幼虫也广泛分布，丰度较低，分布较斑片状，但Eurypharyngidae、Cyematidae和Mongnathidae的幼虫很少见。新喀里多尼亚西部靠近切斯特菲尔德群岛的浅水鳗鱼幼虫数量最多，或在其他岛群附近，但它们在 2016 年经过大溪地两侧的最东端 2 个样带中很少见。一些星鳗被认为是在西部地区的近海地区产卵的。康格瑞德在切斯特菲尔德群岛附近或新喀里多尼亚附近的地区，目前的喷流可以将幼虫向西输送，并且存在向东的逆流，从而产卵了Ariosoma和各种浅水或斜坡鳗鱼。沿海物种的一些幼虫类群（muraenesocids 和 elopomorphs）极为罕见，所有非中层鳗鱼幼虫在远东横断面都很罕见，但具有大陆架面积的新喀里多尼亚地区似乎是海洋生物多样性高的地区鳗鱼，就像一般的珊瑚礁/海岸鱼一样。