Tagging eastern rock lobsters Jasus verreauxi: effectiveness of several types of tag

Abstract

An experiment was done in the laboratory over 147 weeks to assess tag loss (tag-induced mortality plus tag shedding) in tagged or marked eastern rock lobsters, Jasus verreauxi. The incidence of tag-induced mortality, tag shedding or tag loss did not generally differ among tag types (toggle, T-anchor, dart tags), mark, or untagged lobsters. The exceptions were that more untagged lobsters died between weeks 86 and 147 than lobsters tagged with T-anchor or dart tags. The percentages of lobsters that died were 51, 45, 43, 47, and 62 for toggle, T-anchor, dart, marked, and untagged treatments, respectively. An additional 18%, 22% and 23% of lobsters tagged with either toggle, T-anchor or dart tags, respectively, shed their tag. None of the marked lobsters lost their marks. We conclude that no one type of tag used in the experiment was more suited to tagging J. verreauxi than another. Marking was discounted as a technique to use in long-term experiments because, although the mark was still evident after 147 weeks, only trained observers could recognise it, making the technique inappropriate for the general public.