Scientists have spotted a rare false catshark, also known as a “sofa shark”, off the west coast of Scotland. This mysterious species is very elusive, and it’s the second time in more than a decade that such a fish has been encountered in British waters.
The false shark was caught by a team of marine biologists employed by the Scottish government agency Marine Scotland. While conducting a deep-sea survey near the islands of Barra and St Kilda, they encountered a female “sofa shark” which was about 6.5 feet in length and weighed approximately 132 pounds.
The unexpected discovery made by researchers in the Outer Hebrides left them shocked, but after measuring the fish, they quickly released it back into the ocean.
The species, also known as a keel-dorsal shark, has a large, bulgy shape. It looks as if it were a hybrid between a blobfish and an electric eel, with long, narrow eyes and over 200 rows of teeth within each jaw. Very few sightings of this species have been reported, since it prefers to live close to the ocean’s floor, so it can’t be specified exactly how large its population actually is.
The International Union for Conservation of Nature’s Red List of Threatened Species states that currently there is a data deficiency regarding this deep-water shark, but it appears it’s more likely to encounter it in the Northern Hemisphere.
The species has usually been recorded at depths between 656 feet and 6,200 feet, including around seamounts and deep-water coral reefs, but it has also been found in more shallow water, on continental shelves.
Although very little information is available regarding the shark’s behavior, its appearance (large billowy shape, soft fins, skin and muscles) suggests that its lifestyle tends to be sedentary and languid. Researchers also know that embryos belonging to this species indulge in oophagy, which means that they consume the eggs produced by the ovary while still in their mother’s uterus.
This type of intrauterine cannibalism may allow them to grow larger and hone their predatory skills. The practice has been identified before among other shark species, like the grey nurse shark and the gollumshark, and also among certain snake species.
Dietary habits remain peculiar when it comes to false catsharks throughout their entire life cycle. For example, according to findings published in 1992 in the Copeia journal, when researchers studied the stomach contents of these sharks they were left completely baffled.
Aside from the expected deep-sea prey consisting of squid, octopus and smaller sharks, they also identified man-made garbage, such as potatoes, plastic bags and soda cans.
Image Source: PBS