Abstract
Non-lethal methods for semen collection from elasmobranchs to better understand species reproduction has accompanied the development of artificial insemination. Ejaculates (n = 82) collected from whitespotted bamboo sharks Chiloscyllium plagiosum (n = 19) were assessed and cold-stored raw or extended at 4 °C. Females (n = 20) were inseminated with fresh or 24–48 h cold-stored raw or extended semen and paternity of offspring determined with microsatellite markers. Insemination of females with fresh semen (n = 10) resulted in 80 hatchlings and 27.6% fertility. Insemination of females with semen cold-stored 24 h (n = 4) and 48 h (n = 1) semen resulted in 17 hatchlings and fertilization rates of 28.1% and 7.1% respectively. Two females inseminated with fresh or cold-stored semen laid eggs that hatched from fertilization and parthenogenesis within the same clutch. Parthenogenesis rate for inseminated females was 0.71%. Results demonstrate artificial insemination with cold-stored semen can provide a strategy for transport of male genetics nationally and internationally, precluding the need to transport sharks. Production of parthenotes in the same clutch as sexually fertilized eggs highlights the prevalence of parthenogenesis in whitespotted bamboo sharks and poses important considerations for population management.
Highlights
Non-lethal methods for semen collection from elasmobranchs to better understand species reproduction has accompanied the development of artificial insemination
Spermatozoa had elongated helical heads (Fig. 1c) with an apical acrosome that was stained by Arachis hypogaea lectin or peanut agglutinin (PNA) (Fig. 1b–e)
This study demonstrates that offspring can be produced from artificial insemination (AI) of whitespotted bamboo sharks with sperm coldstored for up to 48 h
Summary
Non-lethal methods for semen collection from elasmobranchs to better understand species reproduction has accompanied the development of artificial insemination. Whitespotted bamboo sharks Chiloscyllium plagiosum are endemic to the Indo-West Pacific Ocean and common in aquariums worldwide because of their longevity, successful reproduction under managed care and small size. Gamete cold storage does not require specialized equipment and could be useful in aquariums to allow the movement of genetic material between institutions to maintain gene diversity in a population without the need to transport an animal. This is especially useful as cryopreservation research using elasmobranch semen is limited to a few species of stingray[9,15] and investigation into cryopreservation of semen from whitespotted bamboo sharks has not yielded viable sperm (Wyffels, unpublished)
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