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[Phylum: Chordata] [Class: Chondrichthyes] [Subclass: Elasmobranchii] [Order: Carcharhiniformes]
More than one hundred species of deepwater catshark belong to the family Pentanchidae and most of them are still in existence today.
This section contains some little-known facts about deepwater catsharks, such as where they are found, what they eat, and how these elusive deep-sea creatures reproduce.
Most of the species inhabit some of the deepest marine waters around the world, especially:
Some species are restricted (endemic) in certain areas, like Pinocchio catsharks (Apristurus australis) are only found in southern Australia.
Being typical bottom-dwelling sharks means they thrive best around abyssal plains and deep continental shelves, especially when there is some kind of mud or silt substrate.
The depth range for most deep-water catsharks is typically between four hundred (400) and two thousand (2,000) metres, with some going even deeper to 3,000 metres. Hence, the water is cold and stable below the thermocline, and often only slightly above freezing.
Some adaptations for living in deep sea environments include being energy efficient and having large eyes that can adapt to low-light conditions.
As a consequence of that, the catshark species that inhabit offshore regions have a particularly slow metabolism, a reduction in muscle arrangement, and extra large sensory organs.
Even though most of the genera are small to medium sized, typically between 30 and 80 centimetres long, some will grow to more than one metre in total body length.
The body is long and slender, and they have quite a broad head. Although the skin is soft, they have small dermal denticles that can help with predator protection and streamlined swimming.
Their elusive deep-sea behavioural traits, ghostly eyes, and the dark colouration, are the main reasons why they're frequently called 'demon catsharks' and sometimes 'ghost catsharks'.
They prowl near the ocean floor, using their electroreceptors and keen sense of smell to detect their favourite prey hidden in sediment, such as:
The African spotted catshark is a small, bottom-dweller found near the southern coast of Africa - mainly from Namibia to South Africa.
Like most members of the catshark family Scyliorhinidae, they get their name from the cat-like eyes and the elongated bodies.
In more detail...
They inhabit continental shelves and upper slopes at depths that range from twenty (20) to four hundred (400) metres (1,300 feet).
Having a preference for sandy or muddy seabeds means they can camouflage themselves among rubble sediments. This is where they prey on crustaceans, cephalopods, and small fish.
Adult African spotted catsharks can grow to an overall length around ninety (90) centimeters. But, you can identify them by the light brown to grey body colouring and numerous small dark brown or black spots.
Like most catsharks, they have soft and flexible skin to help them navigate their way through tight crevices and rocky reefs while searching for food in southern Africa's coastal ecosystems.
Even though the African spotted catshark (Scyliorhinus capensis) is not dangerous towards humans, they are caught as a bycatch in some trawl fisheries.
Members of the family Scyliorhinidae are mostly oviparous, meaning the females lay eggs inside robust egg cases (called a mermaid's purse).
It takes almost twelve months for a baby catshark to hatch from an egg. As a consequence, it's not uncommon for some females to hold onto the eggs until they are close to hatching.
The cat sharks that exhibit ovoviviparity, (otherwise known as aplacental viviparous), hold onto the embryos until they are completely developed and then give birth to live sharks.
Many catsharks that live in deep water have weak calcified vertebrae and they lack visible vertical bands (growth bands). Also, most do not have spines on the dorsal fin either - a shark feature often used for ageing the different species.
In the wild, predation in deepwater catsharks comes from some of the large shark species (like sand tiger sharks), and the deepest diving marine mammals (e.g., Southern elephant seals).
That being said, other significant threats come from bycatch, ocean pollution, habitat degradation, and commercial and recreational fisheries.
Important: The IUCN Red List shows the conservation status of most deepwater catsharks is of "Least Concern" (LC). But, in 2020 they listed the blackspotted catshark (Halaelurus buergeri) as "Endangered" with a "Decreasing" population trend.