Abstract

Sand tiger sharks (STS), Carcharias taurus, are a popular, and one of the more common, large sharks displayed in public aquariums. They often live for 10–15 years in managed care situations, with survival times reported well over 20 years.¹ During a relatively long life on display, female STSs go through many reproductive cycles but rarely become pregnant.² Although there have been several successful pregnancies for sharks maintained in flow through systems around the world, there are no reports of a successful conception and live birth having occurred in the USA in either an open or closed system.

Starting in 2015, Ripley’s Aquariums initiated an ongoing effort to induce pregnancy in its STS collection through the use of artificial insemination (AI). Initial AI procedures were completed with cycling females maintained at Ripley’s Aquarium of the Smokies in Gatlinburg, TN, as well as a holding facility in Buffalo, NY. During 2020, the AI research expanded to include STSs maintained in a newly constructed 214,000 gallon tank in Myrtle Beach, SC, to support STS reproduction. Semen was collected from males in the system or from SC coastal catch and release in situ males. Inseminated females were passively monitored for changes in size and shape. Ten months post-insemination, the females were examined using ultrasonography to determine pregnancy status. A STS inseminated on May 5, 2021 was determined to be gravid with one young developing in the right uterus. On March 1, 2022, the gravid female was sequestered in a nursery area in preparation for parturition. Reports in the literature estimate a gestation period of 280–290 days for STSs.^3,4 When the gestation period reached 303 days, the female was evaluated ultrasonographically and the young was confirmed live and determined to be pre-term based on length and gut contents. The female and young were re-evaluated after approximately 3 weeks and the neonate was manually delivered on March 24, 2022. The female was immediately returned to the main population and the neonate remained in the nursery area. The total gestation time was 322 days.

After a brief period alone in the nursery pen, the neonate, nicknamed “Rip,” was placed in a 14,000 gallon holding tank with a variety of small sharks and rays. In addition to morphometrics obtained at birth, Rip was weighed and measured monthly and his diet adjusted based on weight gain and loss. The nutritional goal was to balance growth rate with body condition. At birth Rip was 93 cm total length and 7.9 kg, at 8 months he was 139 cm total length and 17.2 kg.

Acknowledgements

The authors wish to thank the husbandry staff of Ripley’s Aquariums for their efforts and dedication on behalf of this project and elasmobranch conservation.

+Student presenter

Literture Cited

1.  Mohan P, Clark S, Schmid T. 2004. Age and Growth of Captive Sharks. In: Smith M, Warmolts D, Thoney D, Hueter R, editors. Elasmobranch Husbandry Manual: Captive Care of Sharks, Rays, and their Relations. Columbus (OH): Ohio Biological Survey; p 201–226.

2.  Wyffels JT, George R, Christiansen EF, Clauss TM, Newton AL, Hyatt MW, Buckner C, LePagfe V, Latson FE, and Penfold LM. 2022. Reproductive cycle and periodicity of in situ and aquarium female sand tiger sharks Carcharias taurus from the western North Atlantic. Front Mar Sci. 9:925749.

3.  Gilmore RG, Putz O, Dodrill J. 2005. Oophagy, intrauterine cannibalism and reproductive strategy in lamnoid sharks. In: Hamlett WC, editor. Reproductive biology and phylogeny of Chondrichthyes: sharks, batoids and chimaeras. Enfield, (NJ): Science Publishers; p 435–462.

4.  Wyffels J, Coco C, Schreiber C, Palmer D, Class T, Bulman F, George R, Pelton C, Feldheim K, and Handsel T. 2020. Natural environmental conditions and collaborative efforts provide the secret to success for sand tiger Carcharias taurus reproduction in aquaria. Zoo Biol. 39:355–363.