Departmental Bulletin Paper Spawning ecology of Girella punctata and G. leonina (Perciformes: Girellidae) in the coastal waters of the Izu Peninsula, Japan

Nakai, Shizuko  ,  Higuchi, Toshihisa  ,  Iino, Yudai  ,  Itoi, Shiro  ,  Sugita, Haruo  ,  Takai, Noriyuki

38 ( 1 )  , pp.12 - 20 , 2015-07 , International Coastal Research Center, Atmosphere and Ocean Research Institute, the University of Tokyo
The girellid fishes, Girella punctata and G. leonina, are commercially important fishes in Japan, but interspecific differences in their spawning ecology are unclear. In the present study, seasonal variations in the species composition and gonadosomatic index (GSI) were examined for G. punctata and G. leonina collected from the coastal waters of the Izu Peninsula, in order to clarify the spawning ecology of these two species. Both adults and juveniles were genetically identified by PCR-RFLP using mtDNA. The GSI of G. punctata showed markedly high values (>15.0) in April, whereas the GSI values of G. leonina were constantly low (<0.5). This result suggests that the coastal area of the Izu Peninsula is utilized as a spawning ground by G. punctata but not by G. leonina. Juveniles of G. punctata mostly appeared from May to July, whereas those of G. leonina appeared during the longer period from January to June. Juveniles of G. punctata born in the study area are inferred to settle to the sea bottom around the spawning ground after a one-month planktoninc life phase, whereas G. leonina juveniles are likely to be immigrants from another area.

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