The balloon shark or swell shark is a species of benthic catshark belonging to the genus Cephaloscyllium.
The species was first described by Charles Tate Regan, a British ichthyologist. He published his findings in the 1921 issue of Annals and Magazine of Natural History, a scientific journal. Regan’s research was based on a 30 inches long type specimen caught 15-22 miles away from the Umvoti River’s mouth in South Africa.
Balloon Shark Scientific Classification |
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| Kingdom | Animalia |
| Phylum | Chordata |
| Class | Chondrichthyes |
| Order | Carcharhiniformes |
| Family | Scyliorhinidae |
| Genus | Cephaloscyllium |
| Scientific Name | Cephaloscyllium sufflans |
Description
The balloon shark reaches a length of 3.6 feet in its lifetime.
Their dorsal body surface is light gray-brown to purple, leading to a paler ventral surface. The pectoral fins’ upper surface is the same color as the dorsal side. Younger sharks display a series of 6-7 prominent-looking dark saddles along their back and tail, a feature that fades in adults. Their skin is thick and rigid and covered with dermal denticles that are each triangular, pointed, and well calcified.
Their head is stout, firm, flattened, and consist of a short, rounded snout. A narrow lobe on the snout divides each of its nostrils. They have a set of big, horizontally oval eyes covered with nictitating membranes (a layer of additional third eyelid), which are placed higher on their head.
Their mouth is spacious and forms a wide arch. The upper jaw consists of 60 tooth rows, while the lower jaw contains 44 lower tooth rows. Each tooth is made of a solo, central cusp surrounded by 1-2 small cusplets.
They have five pairs of gill slits, with the third pair being the longest.
Located just opposite the pelvic fins is the first dorsal fin. The second dorsal fin, in comparison, is smaller and is present opposite the anal fin. Adult males of this species have thick and short claspers. The pelvic fins are a little lower, and the anal fin, compared to the second dorsal fin, is much larger.
These sharks have a short tail consisting of a caudal fin bearing a small lower lobe and an upper lobe, on whose underside there exists a notch near the tip.
Where do they live
The balloon sharks are found in the waters of the western Indian Ocean. KwaZulu-Natal and Mozambique are the two provinces of South Africa where these shark’s range remains confined.
They inhabit the continental shelf and upper continental slopes. It prefers muddy or sandy waters at depths of 130–1,970 ft. Mostly the juveniles are found in deep waters (130–1,440 ft.) off KwaZulu-Natal. Adults are found in much deeper waters toward the north.
Behavior
Dietary
These sharks primarily feed on crustaceans like lobster and shrimp and some cephalopods. It has also been known to consume bony fishes and elasmobranchs found on the sandy or muddy ocean bottoms.
Reproductory
These sharks follow an oviparous mode of reproduction. The embryos inside the mother shark feed solely on the egg yolk.
Females lay one egg case containing two eggs. Young sharks hatch out of the eggs at body lengths of 7.9-8.7 inches.
Both sexes mature at 28–30 inches.
Adaptations
The balloon shark can inflate its stomach with air or water as a defense mechanism to increase its body size to look intimidating. This mechanism is a common adaptation of species belonging to this shark’s genus.
Interactions with humans
The balloon shark is not a commercially important fish. It is a part of regular accidental catch by bottom trawlers and is usually discarded. That being said, there are no reports to confirm any significant drop in their population.
The IUCN recommends proper monitoring of fisheries to prevent any negative impact on the shark’s population. Therefore, it has classified the species as ‘Near threatened.
No conservation methods or schemes are currently underway to protect this species.
