Giant, Rare Shark Washes Up Somewhere It's Never Been Seen Before

By Aristos Georgiou On 2/15/23 at 10:00 AM EST

Tech & Science Sharks Animals Fish Oceans

A large, rarely seen shark—possibly one of the heaviest of its species—washed up ashore in a location where it has never been recorded before.

The 11-foot-long smalltooth sand tiger shark became stranded on the coast of Galicia in northwestern Spain on June 2, 2022. It is the subject of a study published in Thalassas: An International Journal of Marine Sciences.

A smalltooth sand tiger shark — The smalltooth sand tiger shark that became stranded on the coast of Spain. Little is known about this rare and elusive species. Gonzalo Mucientes

This species (Odontaspis ferox) is found in tropical and warm, temperate oceans around the world, although its distribution is patchy. There have been only a relatively small number of captures and sightings, so little is known about its biology and behavior.

The stranding in Galicia provided a rare opportunity to examine this elusive shark species.

"There are relatively few records suggesting that it is rarely encountered—or reported—or it can be that this shark has low (local) populations naturally," Gonzalo Mucientes told Newsweek. He is the lead author of the study with the Instituto de Investigaciones Marinas, Consejo Superior de Investigaciones Científicas in Vigo, Spain.

The smalltooth sand tiger shark has been recorded further north than Galicia before—off the coast of France, for example. But this active predator had never been observed in Galicia or the surrounding areas.

The researchers said the stranding of the shark here was unusual, given it is normally found in deepwater habitats around islands, as well as on continental shelves and slopes.

"It is surprising because this species mainly lives close to the seabed around islands and underwater seamounts, or in the deep waters of continental outer shelves and upper slopes in the distribution area," Mucientes said.

"The Galician estuaries are characterized by shallow and inland waters with heavy fishing, where it would have been caught if it were more common."

The smalltooth sand tiger shark discussed in the study was a female weighing around 660 pounds. This ranks among the heaviest specimens of this species on record, according to Mucientes.

The maximum recorded weight for this species was around 637 pounds, but there is evidence of individual specimens growing to more than 14 feet in length.

Prior to washing up ashore, the female shark was accidentally caught and released by a small-scale fishing vessel off the northwestern coast of Spain.

The shark became stranded, still alive, on the coast in a small estuary called O Esteiro. It died a few hours later from suffocation.

Mucientes and colleagues confirmed the death of the shark, while also taking body measurements and collecting tissue samples.

They identified the species based on genetic analysis and several characteristic features—such as the long and narrow teeth, long, bulbous snout and the shape of its fins. The smalltooth sand tiger shark is often mistaken for the much more common gray nurse shark.

The researchers observed parasites of the species Anthosoma crissum in the specimen's mouth— commonly found in other sharks. They also found that the shark had no food in its stomach, indicating that it had been migrating in the last days prior to its death.

The available evidence shows that this species might move over large distances by crossing submarine ridges, archipelagos and islands, or seamounts.

"Mature females of this species are likely to migrate to shallower waters in breeding periods and it can appear seasonally and periodically in specific places, as is the case of the El Hierro Island in the Canary Islands," the authors wrote in the study. "However, the nature and explanation of these behaviours remains to be discovered."

The scarcity of smalltooth sand tiger shark sightings or captures could be attributed to its potentially low abundance. It could also be that its deepwater habitat is out of the depth range of most commercial and traditional fishing operations.

The latest study provides new insights with regards to the distribution and occurrence of this rare and sparse species.

There is some concern that the smalltooth sand tiger shark is declining in numbers because of human activities in some regions. But a lack of adequate data means accurate assessments of its conservation status are not available.

The species is protected in the waters of some Mediterranean and Pacific nations, such as Croatia, Spain, Colombia and New Zealand. But, in many other countries, there are no specific protection measures in place.