External and internal tags for the green sea urchin.
Two internal and three external tags were tested on the green sea urchin. Desirable qualities of a tag were high sea urchin survival, retention for at least a few months, detection on the sea floor by divers, identification of individuals, quick application, and low cost. These objectives were met by an external nylon screw tag visible to divers and two internal aluminum tags detectable with an underwater metal detector. Successful tags were inserted through a hole drilled in the test and were tested in the laboratory and field. All internal tags were retained for the full duration of the 4-month trial and did not retard growth or affect survival. Divers could identify individual urchins with nylon screw tags, but the tag retention rate was lower.
Bedford Institute of Oceanography, Department of Fisheries and Oceans, B-100, PO Box 1006, B2Y 4A2, Dartmouth, Nova Scotia, Canada
R E.
RE
Duggan
R J.
RJ
Miller