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Nigorobuna is an endemic fish species in Lake Biwa and is useful in the production of "funazushi", a traditional fermented food in Shiga Prefecture. The importance of a reed community has been confirmed as a nursery area for this species.

The influence of hatching date on the sex ratio of wild Gnathopogon caerulescens was examined. Cohorts reared from eggs collected in the early and middle parts of the spawning season showed almost balanced sex ratios, with female bias in some cohorts. Cohorts born later in the season mostly displayed male bias, and the mean proportion of males later in the season was significantly higher than in early- and mid-season cohorts. These results indicate that the sex ratio of G. caerulescens changes with the time of breeding, increasing along with the ambient water temperature of the lake.

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