抄録
Female red-spotted masu salmon, Oncorhynchus masou ishikawai, collected in a small stream in Honshu Island, Japan, were examined for ovulated eggs, which were not oviposited during the preceding spawning season. Nearly half of the specimens collected in 1984 had some retained eggs in the abdominal cavity. In addition, some females had both well-developed gonads and ovulated eggs, indicating that they spawn at least twice during their lifetime (iteroparity). The smaller the female body size, the more the retention of ovulated eggs and their proportion of the overall egg total. Such eggs are probably resorbed for energy during the non-spawning season, hence improving their growth and/or survivorship and, consequently, future reproductive success.
