| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1998: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1997: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Research Abstract |
Apogonid and syngnatid fishes are representative groups in which sex-roles are reversed. In the sex-role reversed species, female reproductive success is generally limited by availability of males, unlike in the majority of animals. We have investigated life histories and reproductive strategies of some apogonid and syngnatid fishes in Uwa Sea, Shikoku, Japan for these several years. In Apogon doederleini, the most intensively studied species, detailed data were obtained on growth, migration, reproductive success, mate change and filial cannibalism from identified individuals. From analysis of these data, we found that filial cannibalism by mouthbrooding males is the age-specific reproductive stragegy. From the preliminary analysis of fat, protein and carbon contents in body parts of A.doederleini, we examined the physical condition of males who performed filial cannibalism and estimated energetic costs entailed in mouthbrooding. In the pipefish Corythoichthys haernatopterus, we found that pair-bond is usually maintained throughout the entire breeding season and that serial monogamy is due primarily to mate guarding by females.
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