1Graduate School of Agricultural Sciences, Tohoku University, Miyagi 981-8555, 2National Research Institute of Aquaculture, Mie 516-0193, Japan
Usefulness of Coded Wire Tag made of stainless steel for the sea urchin Strongylocentrotus nudus (A.Agassiz) was examined by rearing experiments. Tags were inserted in the peripharyngeal cavity of sea urchins. Effects of tagging on the growth and mortality were not found. The lost tags in % for 7 days increased for thefirst 14 days after tagging, showing size-dependent difference, and thereafter abruptly declined and kept a low value after 21st day, without showing difference among size class. Estimation of the % of lost tags for any time became possible using a regression equation of the accumulated % of lost tags on the elapsed day from the 21st day after tagging.