New Shark Added To Bermuda’s Fish Fauna

September 26, 2022 | 

A new species of shark – the Ragged-tooth shark –  has “now been officially added to list of fishes found in Bermuda waters.”

In a recent edition of the Envirotalk newsletter, Dr. Joanna Pitt said, “A new species of shark, the Ragged-tooth shark [also known as the Small tooth sand tiger and, scientifically, as Odontaspis ferox], has now been officially added to list of fishes found in Bermuda waters. As often happens, the first encounter with this species was at the end of a fishing line.

“A commercial fishing vessel, captained by Mark Terceira, was fishing in 731 metres [2,400 feet!] of water off the east end of the island on the 19th of August, 2020, using deep set vertical lines to target deepdwelling species such as Wreckfish. The shark did not actually take the bait, but one of the hooks snagged in its dorsal fin. Mr Terceira brought the shark to the surface alongside the vessel, and snapped a few photos before releasing the shark alive. He estimated the total length of the shark to be about 275 cm [9 feet].

Ragged-tooth shark caught in 2020 by commercial fisherman Mr. Mark Terceira and subsequently released

“These photos were shared with DENR’s Marine Resources staff in order to facilitate identification of the shark, and also posted online. The post came to the attention of Dr Jeremy Higgs of the Gulf Coast Research Lab at the University of Southern Mississippi, who has been tracking observations of the Raggedtooth shark, and a flurry of emails ensued. Much of the information that follows comes from the recent article that Dr Higgs published with some colleagues, which constitutes the official record of this species for Bermuda.

“Fortunately, Mr Terceira’s photographs captured all the key identifying features of this species, including the distinctive shape of its head, and the relative size, shape and placement of the fins [Figure 1 a and b]. The flattened head with a long, conical snout, large first dorsal fin compared to the second dorsal, and even grey-brown coloration are important identifiers of the Ragged-tooth shark [Figure 2]. In contrast, the Bigeye sand tiger [Odontaspis noronhai] is dark brown, with a white tip on the dorsal fin, and has a much larger eye – as you might expect from its name. The Sand tiger shark, Carcharias taurus, which has also been encountered in Bermuda waters under similar circumstances, is pale grey with darker blotches and has a very different fin pattern. Of course, you can always examine the teeth of a shark to help confirm its identity, but few people are willing to do this on a live specimen.

“The Ragged-tooth shark is known to inhabit tropical, subtropical and temperate marine waters around the world, and is often associated with the deep shelf or slope habitats of both continents and islands. However, reports of this species are rare, and mostly consist of isolated observations. Captures or sightings from places as distant as the Canary Islands and New Zealand indicate this species inhabits depths as shallow as 1 m and as deep as 928 m [3.5 to 3,000 feet], although shallow encounters are rare. As a result, even shark experts know little about the life cycle of this species because of the small number of specimens that have been examined.

“The photographs showed that the Bermuda specimen was a male and, based on its size and the length of its claspers, likely mature [Figure 1a]. The largest Ragged-tooth shark on record is a female that was 520 cm long [17 feet], caught in the open waters of the southeastern Atlantic Ocean. This species bears live young, and females become mature at lengths of 300–350 cm [10-12 feet], while males are approximately 200-250 cm [7-8 feet] long when they mature. The pups are approximately 100 cm long [3.3 feet] at birth. Based on the biology of closely related species of lamnid sharks, it is assumed that this species produces only two pups per year

“With this extremely low predicted birth rate and the general paucity of information about the species, the International Union for the Conservation of Nature [IUCN] has assigned a precautionary assessment of “Vulnerable” for the Ragged-tooth shark on their Red List of Threatened Species. The Red List is considered the most comprehensive inventory of the conservation status of animals globally.

“A common feature of the case studies that form the basis of Dr Higgs’ article is that each shark was encountered as a result of fishing in deep waters [>300 m / 990 feet]. As fisheries activities have expanded into deeper water, they have also begun to overlap with the known depth range of the Ragged-tooth shark. As this expansion continues, interactions with the Ragged-tooth shark will likely increase, highlighting the importance of fishery observations to provide insight into the distribution of this species.

“This first record of the Ragged-tooth shark from Bermuda waters is the deepest known capture of this species in the North Atlantic Ocean to date. Previous studies on the deep slope around the Bermuda platform noted Lophelia deepwater corals in the area where Mr Terceira was fishing, and these corals have also been present in conjunction with other observations of Ragged-tooth sharks from the western North Atlantic. Dr Higgs believes that future studies should investigate both deepwater coral habitats and deep slope areas around the region in an effort to further describe the preferred habitat of Ragged-tooth sharks. With a better understanding of their distribution and habitat preferences, it may be possible to adjust fishing practices in order to reduce the chances of capturing this vulnerable species.

“This newly recorded species is automatically protected under the recent legislative amendments that were made to protect and manage sharks in Bermuda waters, which were passed in March of this year. There is now a general prohibition on taking sharks, although commercial fishers may apply for a special licence to catch limited amounts of three common species: the Galapagos shark, Carcharhinus galapagensis [locally called a Dusky shark]; the Smooth dogfish, Mustelus canis [which Bermudians refer to as a Gummy shark]; and the deep-dwelling Six-gill shark, Hexanchus griseus.

“For more information about the Ragged-tooth shark / Smalltooth sand tiger, along with some great photos, see here For the new report of this species in Bermuda waters, refer to Higgs, Hoffmeyer, Driggers, Jones and Hendon [2022], ‘New records of the ragged-tooth shark, Odontaspis ferox, from the western North Atlantic Ocean, with a summary of regional occurrences’, published in volume 98 of the Bulletin of Marine Science. A summary of this paper is available online here, a hard copy is available in the library of the Natural History Museum at BAMZ, or you can request a pdf by emailing fisheries@gov.bm.”