A study of two tagging methods in the Caribbean sea cucumber Holothuria mexicana

Abstract

An effective tagging technique represents a challenge for long-term studies in sea cucumbers. These studies require accurate identification, high tag retention and no adverse effects on vital rates or performance of the tagged individuals. We tested the retention rate of one external and one internal tag in the sea cucumber Holothuria mexicana . The passive integrated transponder (PIT) tag was inserted into the coelomic cavity and the T-bar (external tag) was attached in the upper surface of the body wall. Retention rate was lower, for both kinds of invasive tags, than required in long-term studies. Stress elicited by the tagging procedure caused evisceration of 40% of PIT-tagged individuals versus a 57% of T-bars during or no more than five minutes after tagging. No differences in evisceration between both tags were detected; nor any correlation between evisceration and length. To conclude, the tagging procedure harmed the animals and both PIT-tags and T-bars showed similar low retention rates after ten weeks. Both marks were not effective for long-term studies in Holothuria mexicana .