Natural environmental conditions and collaborative efforts provide the secret to success for sand tiger shark Carcharias taurus reproduction in aquaria

Abstract

Sand tiger sharks are an iconic large shark species held in aquaria worldwide. They rarely reproduce under managed care, with only seven aquaria reporting limited and sporadic success. For the first time in the Americas, a full-term young was born in an aquarium. The young was the result of breeding among a group of sharks purposefully brought together in 2016 for reproduction. Sharks were maintained in natural seawater and exposed to natural light and seasonal temperature fluctuations similar to their in situ counterparts. Decreased food consumption associated with breeding season and gestation was observed. Gestation time estimated from breeding observations and parturition was 321 days. Although the neonate was stillborn, this was a significant achievement. The husbandry details described within will be useful for other aquaria striving to support the reproduction of sand tiger sharks.

Reproductive Anatomy of Chondrichthyans: Notes on Specimen Handling and Sperm Extraction. II. Sharks and Chimaeras

“…Some shark species have never been able to reproduce in captivity or have done so anecdotally [ 16 ]. The captive breeding of one of the most emblematic sharks, the sand tiger shark ( Carcharias taurus ), has only been possible after years of effort and dedication of multiple institutions and researchers, even when this shark species has been kept in aquarium facilities for more than a century [ 82 ].…”

Reproductive Cycle and Periodicity of In Situ and Aquarium Female Sand Tiger Sharks Carcharias taurus from the Western North Atlantic

“…Duration for the retaining stage calculated from the first observation of retaining at a physical examination to a reported egg shedding event was 301 ± 55 days. A single postpartum blood sample was collected in April from a female that was successfully mated and became pregnant during the study timeframe (Table 5) (Wyffels et al, 2020a).…”

“…Aquariums have included sand tiger sharks in large mixedspecies exhibits for nearly a century (Koob, 2004), but they do not readily reproduce in managed care (Henningsen et al, 2017;Willson and Smith, 2017;Wyffels et al, 2020a). Sharks are observed mating, but young rarely result.…”

“…During late gestation the ovary is no longer vitellogenic and the embryo relies on internally stored yolk from its distended yolk stomach. Gestation is estimated to be 280-300 days and parturition occurs in late winter or early spring depending on location, with more northern locations lagging behind warmer southern locations (Gilmore et al, 2005;Wyffels et al, 2020a).…”

“…The reproductive status of sand tiger shark females can be described as active or resting, based on ovarian activity and uterine contents. During an active year, females in the WNA undergo vitellogenesis in spring, are gravid during summer, fall and winter, and give birth in late winter and early spring (Gilmore et al, 2005;Wyffels et al, 2020a). Females in a resting year are not gravid and possess an avitellogenic or quiescent ovary during the same seasons.…”