Sand tiger sharks are popular in aquariums as a representative of an iconic, though poorly understood, ocean predator. Although sand tiger sharks have been under managed care for nearly 100 years, aquarium reproduction remains elusive as there have been only 15 live births. To improve their conservation status, aquaria are uniquely poised to serve as frontline research institutions that can fill critical data gaps about wild and managed sand tiger sharks, while also serving as an effective, trusted platform to improve public appreciation and help drive the conservation of this threatened species. The ongoing demand for shark fins, meat, and other products like squalene, which is produced by shark liver and used in vaccine development, continues to drive overexploitation of sharks and rays globally. Sand tiger sharks have among the lowest reproductive output of any shark with a maximum of 2 pups produced every 2 years, and females have alternating migration patterns that coincide with gestation and resting years of their biennial reproductive cycle. Although reproduction occurs biennially, migration of the Northwest Atlantic population of sand tiger sharks is annual, sex- and size- segregated, and spans nearly the length of the East Coast. For natural or assisted reproduction to be successful in aquaria, the reproductive cycles of both sexes must be synchronized using appropriate environmental and hormonal cues, and precise knowledge of ovulation is needed. Successful ex situ reproduction requires a better understanding of the ecological patterns, health, and environmental conditions that may affect reproductive success under managed care. It will also demonstrate to the public the important role that aquariums play in the recovery of threatened species.
In 2014, a coalition of 13 aquariums and SEZARC convened and formed the Sand Tiger Shark Consortium to address the poor reproduction of sand tiger sharks in aquaria, lack of knowledge of their reproductive ecology and physiology, and to better educate the public about this species. Across 3 workshops, the Consortium identified key action items for sand tiger shark management, including research that revealed attenuated seasonal hormonal profiles of male sharks maintained in aquaria with no seasonal changes, and poorer semen quality than wild counterparts. Our research continues with several main objectives: 1) Expand acoustic and satellite tagging of sand tiger sharks in all life stages to better understand seasonal environmental parameters associated with reproduction in the wild; 2) Use this information to study the effects of manipulating temperature, photoperiod, and other variables in aquaria on sand tiger sharks; 3) Characterize sand tiger shark aquarium habitat use and provide recommendations to promote wellbeing; 4) Synthesize results for a series of public outreach materials, including an interactive digital story map, to promote public understanding of and stewardship for sharks of the world.
