EARLY INDIVIDUAL ELECTRONIC IDENTIFICATION OF SEA BASS USING RFID MICROGLASSTAGS: A FIRST EXAMPLE OF EARLY PHENOTYPING OF SEX RELATED GROWTH

摘要

Although individual electronic tagging using PIT (Passive Integrated Transponder) tag is well established, it is mainly for fish > 60 mm in length. Because electronic tagging still is the ideal identification method, we tried a new microglass RFID (Radio frequency Identification) tag (6 mm in length, 1 mm in diameter, 10 mg in mass) in order to characterize individual fish in very early stages. We used a group of400 sea bass, Dicentrarchus labrax, (200 untagged control fish and 200 tagged fish; range200-1000 mg), and we studied the effects of intracoelomic tag implantation (Cousin et al, 2012) on different endpoints: survival and tag reading, growth over 6 months, and swimming responses. To this end, dead fish were counted daily, biometries were performed at three weeks interval, and fish were sexed at the end of the experiment. Behavioural swimming responses to a sudden dark change challenge were evaluated following the first three biometries (immediately after tagging, 3 and 6 weeks later). After 6 months, a survival of 71.5 % was reached, the smallest surviving fish weighed 197 mg at tagging, and success in tag reading after 63 days was 78.9 % for a size class 300-400 mg at tagging. No negative effects on growth were observed, and mortality mainly occurred within the two first weeks after tagging with a first peak after 5 days. No significant differences in behavioural responses could be detected between tagged fish and untagged controls after 3 and 6 weeks post tagging but differences were seen immediately after the surgical procedure with tagged fish being over reactive. Overall, results suggested that the tagging method was highly suitable for sea bass as small as 300 mg, and we were able to use it for a first evaluation of early growth differentiation between sexes, females being 31 % heavier than males even at the first measurement (635 mg mean mass). Such an early tagging method is essential to run longitudinal monitoring of individual biological traits (e.g. growth) or to repeat assays with the same individual at discrete points in time (e.g. behaviour studies). Further, the method has a great potential to enable selection on early expressed characters hence saving rearing costs.