Recognition software successfully aids the identification of individual small-spotted catsharks Scyliorhinus canicula during their first year of life

Abstract

Eighteen captive small-spotted catsharks Scyliorhinus canicula were successfully identified from hatching to 1 year of age using the free computer recognition software, I3S classic. The effect of increasing the time interval between recognition attempts on the accuracy of the software was investigated, revealing that recognition fiedelity decreases with increasing time intervals for younger (0 to 15 weeks), but not older (15 weeks onwards) sharks. Identification by I3S was validated using genetic analyses of seven microsatellite markers, revealing a 100% success rate. Thus, this non-invasive recognition method can be used as an inexpensive and effective alternative to invasive tagging, improving animal welfare and complementing ex-situ conservation methods.