The warty sea cucumber, Apostichopus parvimensis, is one of two commercially fished sea cucumber species along the California coast, ranging from Point Conception to Puerto San Bartolome in Baja California, Mexico. A. parvimensis is becoming a species of interest for aquaculture because of its high market value, over-fished status, and suitability for integration in multitrophic aquaculture systems. To facilitate aquaculture development (e.g. broodstock management) and research, there is a need for reliable, non-invasive, tagging of A. parvimensis. We therefore evaluated tag retention, growth, and survival in A. parvimensis using four different tag types.
Wild-origin adult A. parvimensis (52-178 g in size) were acclimated to captivity and randomly assigned to one of four treatment groups of 10 animals each, plus a control group. Treatments included: 1) a Floy tag inserted in the musculature band (FT-M), 2) a Floy tag inserted into a papillae, or “wart”, (FT-P), 3) a Passive Integrated Transponder tag on monofilament fishing line threaded through the body wall (PIT), and 4) a Visible Implant Elastomer tag (VIE) injected subcutaneously into the upper dorsal surface. The Control group was handled and cared for in the same way but without any tagging. All individuals were assigned to their own tank with flow-through seawater under ambient conditions and were measured weekly. At the end of the 12-week experiment, FT-M, FT-P, and VIE had the highest retention rates of 60%, 50%, and 40%, respectively. All individuals in the PIT group lost their tags. In the treatments that retained tags, average body weight decreased between the start and end of the experiment; the control group increased in size by an average of 11.9g over the 12 weeks. Only one mortality occurred, coming from the FT-P group.
Our findings conclude that external tags are difficult to retain for long-term holding of A. parvimensis and may need to be monitored frequently and retagged as necessary. VIE tags using larger marks and focusing on color combinations (yellow and orange) that are most visible, is a possible future area of research, as this was the least invasive procedure.