Drilling position of the ear affects growth and mortality of scallop ( Patinopecten yessoensis, Jay) in ear-hanging culture

Abstract

We evaluated the effect of where the hole is drilled in the shell when using the ear-hanging or Nimai-ake method in scallop aquaculture. We examined its influence on growth and mortality during 8-month growth trials on the scallop Patinopecten yessoensis at Shikabe, Japan. Our observations showed: (1) no differences in growth and mortality between drilling the hole in the posterior compared to the anterior ear; (2) that drilling at positions next to the ligament causes increased mortality; (3) that the lowest increase in shell height and total weight is obtained when the hole is drilled next to the ligament on the anterior ear; and (4) that growth is greatest when the hole is drilled near the corners of the ears (either on the anterior or posterior ears).