Journal of the Graduate School of Biosphere Science, Hiroshima University Volume 50
Reconstruction of the migratory history of the catadromous fourspine sculpin Cottus kazika from the Monobe and Shimanto River, Kochi prefecture in southern Shikoku, using otolith Sr/Ca concentration ratios
The fourspine sculpin (Cottus kazika) is a catadromous member of the family Cottidae that is endemic to Japan. Our objective was to evaluate the utility of using sagittal otolith Sr/Ca concentration ratios to document the movement of juvenile sculpin between the estuarine areas and freshwater of the Shimanto and Monobe Rivers in southern Shikoku. We confirmed the daily periodicity of increment formation and the correlation between the otolith Sr/Ca ratio and ambient salinity at laboratory condition. Otolith profiles suggested that juveniles tended to move from seawater to freshwater at the beginning of March in both river systems.