November Elasmobranch of the Month: Bigeye Sand Tiger Shark
Updated: Dec 12, 2019
Bigeye Sand Tiger Shark
Bigeye Sand Tiger sharks are large, bulky sharks uniformly reddish brown to black in color, reaching lengths of 3.6 m (12 ft). The first dorsal fin is large, slightly rounded, and sometimes has a light-colored blotch at the tip. The second dorsal fin is approximately half as large as the first. The pectoral fins are also rounded at the tip, broad and medium-sized. The pelvic fins are slightly smaller than the first dorsal fin. They have large, orange eyes that do not have a nictitating membrane. (A third eyelid that can be moved to cover the eye for added protection) This shark’s teeth are long and pointed. Each tooth has a main cusp with a smaller cusplet on each side. The teeth of the upper jaw curve slightly down and back, while the teeth of the lower jaw curve up and back.
Bigeye Sand Tiger ready for release after capture and tagging. Image retrieved from https://nsuworks.nova.edu/
Habitat and Distribution
This Bigeye Sand shark’s distribution is not well known. Limited records indicate its range includes tropical and subtropical regions of the Indian, Pacific and Atlantic oceans. There is some speculation that its distribution may be global. They inhabit the deep ocean waters between 60 –1,000 m (200–3280 feet). They have also been caught at night in more shallow waters, resulting in the hypothesis they may move into shallower depths after dark to feed.
Map IUCN Red List
The teeth of the Bigeye Sand Tiger are designed for grasping prey, which they likely swallow whole. Their diet consists predominately of fish and squid.
Figure 2. Detailed views of teeth in a bigeye sand tiger Odontaspis noronhai captured and released in the western North Atlantic in March 2008 ( retrieved from https://nsuworks.nova.edu/)
This shark species reproduces ovoviviparously (aplacental viviparity). Eggs develop inside the female, being nourished by a yolk sac before consuming additional eggs produced by the mother. Additional information on gestation period and litter size is not known.
The Bigeye Sand Tiger shark is listed as “Data Deficient” on the IUCN Red List of Threatened Species.
Bigeye Sand Tiger sharks are not targeted by commercial fisheries or recreational anglers. They will occasionally be caught as bycatch by deep water fisheries. Natural predators of this shark species are not known.
Ocean For Sharks
The IUCN Red List of Threatened Species
Kyne, P.M. & Ebert, D.A. 2019. Odontaspis noronhai. The IUCN Red List of Threatened Species 2019: e.T39336A2899894. Downloaded on 27 October 2019