Abstract
Eight silver‐phase male Indo‐Pacific eels (giant mottled eels) Anguilla marmorata were collected from three small rivers on subtropical Amami‐Oshima Island, Japan, and their morphological and gonadal‐histological characteristics were examined. The total length, body mass and age of the silver eels were 543.8 ± 49.3 (496–659) mm, 376.0 ± 116.0 (282–660) g and 14.6 ± 2.3 (11–19) years old, respectively. The silvering‐related characteristics (eye index, pectoral‐fin index, gut‐somatic index) and reproductive characteristics (gonadosomatic index, histological stage) of the silver eels were significantly advanced compared to those of yellow eels, which is similar to other anguillid species.