Abstract
To improve methods for developing and maintaining short-necked clam fishing grounds in cold regions, the relationship between short-necked clams and ground environment was investigated. Density of young short-necked clams decreases as the ground becomes harder. Daily dry-up time in short-necked clam habitats in Hokkaido are longer than in either Kyushu or the Inland Sea, and temperatures are rarely over 30°C . Therefore, ground temperatures don't inhibit shortnecked clam growth. When seas and lakes freeze, because ice tends to attract sand in areas with smaller grain size sediment, mud can't accumulate in fishing grounds and young short-necked clam density decreases.
