Early life-history characteristics of Conger leptocephali in the western South Pacific

Abstract

Context Conger eels in temperate regions migrate offshore to reproduce in similar ways as anguillid eels do, but little is known about Conger life histories in the western South Pacific (WSP). Aims To show the larval distribution and size, species composition, and early life history of WSP conger eels. Methods Morphological and genetic species identification and otolith analysis were conducted using 71 Conger leptocephali individuals collected in five station-transects from 10 July to 3 October 2016 during the KH-16-4 cruise. Key results We found C. cinereus, C. monganius, C. verreauxi and Conger sp. 1 leptocephali. Possible spawning areas of C. cinereus and C. verreauxi were discovered, and C. verreauxi appears to migrate offshore to reproduce. Growth rates of the four conger eels were higher than those of temperate Conger species, and of Anguilla leptocephali that were collected in the WSP. Conclusions Aspects of the Conger species composition, spawning areas and larval distributions were shown. Conger leptocephali grow faster than do Anguilla leptocephali in the WSP, probably because Conger larvae have larger maximum sizes. Implications Our findings have improved understanding of the early life history of Conger species and highlighted need for further studies about life histories of Conger in the Indo-Pacific region.