Rare ‘Sofa Shark’ Caught Off Scotland’s Outer Hebrides

Marine biologists have discovered a sofa shark, a rare and unusual species of elasmobranch, swimming in Scottish waters as part of a deep sea survey near the islands of Barra and St. Kilda.

Scientists from Marine Scotland noticed the shark during their survey in the Outer Hebrides, and brought it aboard their vessel. Researchers were able to determine that the shark was a female, weighing roughly 60 kg, according to AOL Travel. Though the scientists involved in the survey were not familiar with the species, careful research led them to conclude that it was in fact a false catshark (Psuedotrakias microdon) which is also commonly known as a sofa shark.

Sofa sharks are thought to be exceedingly rare, spending the majority of their time at depths between 1,600 ft and 4,600 ft. Primarily scavengers, they remain near the sea bottom, feeding on fish and other invertebrates. The sofa shark closely resembles the blobfish, and is often identified by its keel-like dorsal fin. The species can reach lengths of just under 10 feet, and are usually dark brown or light grey in color. Sofa sharks exhibit narrow eyes and a large mouth, which is filled with rows of small, sharp teeth.

The Scottish Shark Tagging Programme asserted that the sofa shark is a species which has not been observed in Scotland’s waters in the past. Environment secretary Richard Lochhead recalled, however, that a single sofa shark had previously been recorded in the region, as the Scotsman points out. Scientists with Marine Scotland reportedly observed one of the animals while conducting a survey north of Vidal Bank in 2000. That sighting was located just a few miles from where the sofa shark was recorded this year. Both specimens were observed on the same section of the shelf slope that is located north of Vidal Bank, roughly 50 miles southwest of the Isle of Barra.

Though the sofa shark may look strange, it is hardly the only member of the elasmobranch family to be found near Scotland (elasmobranchs include sharks, skates, and rays). The Scottish Shark Tagging Programme noted that last year, they compiled the first authoritative list of elasmobranchs to be found in the region, along with help from Marine Scotland and the Shark Trust. With the addition of the sofa shark, there are now 72 different species of shark that have been documented as part of their findings.

A spokesman for the tagging programme noted that the sofa shark was a welcome addition to their list of known elasmobranchs. He pointed out that in the recent past, it was believed that no more than 32 species of shark swam in Scottish waters. Many of the new additions to that list have been found in deep water.

The sofa shark is hardly endemic to Scotland, and has been recorded in both the western Atlantic and the Pacific Ocean. The species is rarely caught, as it is neither targeted by fisheries nor valuable in a commercial sense, and conservationists lack solid data regarding their distribution. The sofa shark generally gives birth to two pups at a time, and it is thought that the species’ low reproduction rate may leave it vulnerable to population decline.

Researchers asserted that the sighting of the false catshark was an unexpected bonus amid their work on the survey. Marine biologist Francis Neat noted that once the team weighed and measured the sofa shark, they returned it to the sea.

[Photo by NOAA Northwestern Hawaiian Islands Expedition 2003 via Flickr | CC BY 2.0]