Effect of implanted PIT-tags on growth, survival, and tag retention in the sea urchin Tripneustes ventricosus

摘要

The major goal of this study was to provide valuable information about the effectiveness of tagging the whitish sea urchin Tripneustes ventricosus in semi-captivity conditions using one type of internal mark. A field experimental study was conducted to assess the effect of Passive Integrated Transponders (PIT) tagging on the survival and growth rate of T. ventricosus as a function of body size, and evaluate PIT tag loss. PIT tags were injected into the coelomic cavity of sea urchins ranging from 29 to 125 mm of test diameter (TD). Sixty sea urchins (30 tagged and 30 non-tagged) of similar sizes were monitored over 10 weeks. For all sea urchin size categories, at the end of the study, tag retention rate was 100, and survival rate was 75.0 +/- 24.0 . Small-sized urchins exhibited the highest Gross Growth Rate during the experiment (tagged: 3.16 +/- 0.34 mm TD; control: 1.78 +/- 0.36 mm TD), whereas large-sized individuals displayed the lowest rates (tagged: 0.53 +/- 0.0 mm TD; control: 0.70 +/- 0.18 mm TD). No significant differences in survival and growth rates were found between tagged and non-tagged animals within size classes. Results suggested that urchins can be tagged using PIT tags, with negligible effects on survival and growth, and this leads to a zero tag rejection rate. Therefore, we recommend use this accurate technique to improve estimation of demographic parameters in T. ventricosus populations for long term tagging studies.