The effects of temperature and salinity during the summer months on the annual fisheries yield of Corbicula japonica at Lake Shinji

• Published in: Japanese Journal of Limnology (Rikusuigaku Zasshi) Vol. 77; no. 2; pp. 175 - 181
• Main Authors: YAMAMURO, Masumi, KAMIYA, Hiroshi
• Format: Journal Article
• Language: Japanese; English
• Published: The Japanese Society of Limnology 2017
• Subjects: growth rate; low water temperature; recruitment
• ISSN: 0021-5104; 1882-4897
• DOI: 10.3739/rikusui.77.175

To estimate the effect of water temperature and salinity on the biomass of Corbicula japonica at Lake Shinji, the correlation between average monthly temperature and salinity (electric conductivity) of surface waters and annual fisheries yield (one and two years following water monitoring) was examined. Temperature and salinity data from June, temperature and salinity from July, temperature from August, mean temperature from June and July, mean salinity from June and July, mean temperature from July and August, mean salinity from July and August, mean salinity between June and September, minimum salinity between June and September, and maximum salinity between June and September were investigated. To detect possible differences in monitoring position, we analyzed data obtained from three locations (near the freshwater entrance, center of the lake, near the saline water entrance) between 1985 and 2012. The strongest correlation was between the temperature from June and the annual fisheries yield for the following year. No differences in June temperatures were detected between monitoring positions. We then added the data from the surface water temperature at the center of the lake in June between 1972 and 1983 to analyze correlations with the annual fisheries yields from the following year, and obtained a significant positive correlation (r = 0.52, p < 0.001). This denotes that the biomass of C. japonica decreases as a result of low water temperature in June, possibly owing to decreased growth rate.