1Hokkaido Central Fisheries Experimental Station, Yoichi, Hokkaido 046-8555, 2Oshima-Toubu Fisheries Extension Office, Minamikayabe, Hokkaido 041-1613, 3Rumoi-Nanbu Fisheries Extension Office, Rumoi, Hokkaido 077-0027, Japan
This study examined the effects of current velocity and direction on the growth of the Japanese scallop Patinopecten ( Mizuhopecten) yessoensis in hanging culture. Scallops of 1-year-old were suspended from four surfaces of a cubic frame with exhalent margin (posterior) oriented outside, and placed in cultivation areas of Shikabe and Mashike, Hokkaido, Japan, for eight and eleven months, respectively. In Shikabe, the growth of scallops with inhalent margin (anterior) oriented NNW was highest, whereas that of scallops with posterior oriented NNW was significantly lower. The growth of scallops in Mashike with anterior oriented SW and NW was significantly higher. The current component of S-SE and NE-ESE with speed of <10 cm/s was dominant in Shikabe and Mashike, respectively. The results suggested that the presence of dominant current from a specific direction affected the growth of hanging cultured scallop: the feeding was enhanced and inhibited by anterior and posterior oriented dominant currents with speed of <10 cm/s, respectively.