Physical and chemical tagging methods for the sea urchin Paracentrotus lividus (Echinodermata: Echinoidea)

The sea urchin Paracentrotus lividus (Lamarck, 1816) (Echinodermata: Echinoidea) is an important economic resource in Europe, but intense harvesting has led to the collapse of several natural populations. Echinoculture, associated with restocking and stock enhancement practices, is an alternative to this problem. In these procedures, reliable individual identification through tagging is a valuable source of information. However, very few studies address the effect of tagging methods on P. lividus and the tagging of marine invertebrates still presents several challenges: decreased growth, high mortality rates and low tag retention rates. Under laboratory conditions, the present study evaluated the effectiveness of three tagging methods (passive integrated transponders [PIT-tags], coded wire tags [CWTs] and calcein) on wild P. lividus for 60 days in terms of total wet weight, total weight gain (mg ind.−1 day−1), survival and tag retention. The final total wet weight was significantly higher in the untagged (control) group than in the PIT-tagged group. Survival rate was 100% for the PIT-tag, calcein and control groups, and 97% for the CWT group. Tag retention differed significantly according to the tagging method: 100% in the calcein group, 76.7% in the PIT-tag group and 38.0% in the CWT group.