First analysis of multiple paternity in an oviparous shark, the small-spotted catshark (Scyliorhinus canicula L.).

Multiple paternity (MP) has been demonstrated in a variety of sharks, although its prevalence and the number of sires per litter vary considerably among species. To date, such analyses have focused on viviparous species that possess only part of the wide spectrum of reproductive strategies developed in elasmobranchs. We analyzed MP in an oviparous species, the small-spotted catshark (Scyliorhinus canicula). In total, 150 neonates originating from 13 different mothers were genotyped using 12 microsatellite loci. MP was commonplace, with progeny from 92% of females sired by multiple males. This result is consistent with the reproductive biology of the species, particularly its protracted breeding season and potential for long-term sperm storage. The significance of these findings is discussed in light of small-spotted catshark behavior, which suggests that the cost of avoiding mating attempts initiated by males may be high and is therefore supportive of convenience polyandry as an explanation for MP. Eggs were followed from the time they were laid to when they hatched, offering a rare opportunity to investigate juvenile development in more detail.