Characteristics of the distribution of surf clam and physical environment around port in open sandy beach

Surf clam Pseudcardium sybillae which lives in sandy beaches along the open sea is important fishery resources at Tomakomai coast. Characteristics of the distribution and the growth of the clam around harbor structures are studied from field observation. Environments of food and sediment for the clam are investigated. It was found that the Population of young clam increased around Tomakomai-port by its accumulation effects.