Swellsharks are something strange indeed. They are able to expand their stomachs with gulps of water and greatly increase their size to wedge their bodies in rock crevices, away from predators. They are known to “bark” which surprised scientists, because these sharks lack the sound-producing organs found in some bony fish. Researchers believe that the barking sound is produced when the swellshark gulps air and presses it out back out. It’s another example of how sharks continue to surprise us.
Cephaloscyllium isabellum has been somewhat of a taxonomic wonder itself since its first description in 1788. Unfortunately the holotype of C. isabellum was reported lost in 1979. The group is extremely taxonomically confusing, and scientists have had trouble identifying specimens over the past century. Confirmed off the coast of New Zealand, there have been reports of a similar shark in Taiwan and Japan waters, but scientists are uncertain whether it’s actually C. isabellum, a known sister species or perhaps a new, undescribed species of swellshark. This example helps highlight the importance of taxonomic clarity.
Distribution: New Zealand
Habitat: Rocky and sandy bottom from shore to 673 meters deep, most shallower than 400 meters.
Biology: Oviparous. Eats crabs, worm, other inverts and possible bony fish.
Status: IUCN Red List: Least concern
*Brought to you by Sharks of the World, 2014.
FAO Species Catalogue. Vol 4: Sharks of the world, Part 1 – Hexanchiformes to Lamniformes.FAO Fisheries Synopsis No. 125, 4 (1): 1-250