August Elasmobranch of the Month: Prickly Dogfish
Updated: Dec 12, 2019
Prickly dogfish Oxynotus bruniensis
Key Features: The Prickly dogfish is one shark that definitely has highly distinguishable features! Most notably is its dorsal fin resembling a sail. The dorsal fins have broad and triangular ( sail like) with spines, where the first has a backward inclination and have no anal fin. Its head is relatively flat with two large nostrils at the snout and from what is known the shark can reach at least 75cm! The sharks skin is extremely rough (so much so that the dermal denticles can be seen) and the coloration ranges from brown- grey. Their skin characterizes this shark genus “Oxynotus” (“Oxys” = rough “noton” = back), therefore giving them the common name the “rough sharks”. They are approximately 24 cm long when they are born with males reaching a length of 60 cm and females reaching 72 cm. They are aplacental viviparous, with females giving birth to approximately 7 pups.
Image: 2005 NOAA Ocean Explorer
Where is it found: This curious species is found in the South Pacific, more specifically in southern and western Australia as well as New Zealand. The species are deep dwelling, along the outer continental shelves and upper slopes. The maximum depth reported for the prickly dogfish is 1,067 meters! Most commonly reported at 350-650 meters.
Diet: It is thought to be a slow moving predator, feeding on small benthic organisms. DNA sequencing has shown that they prey on the egg cases of holocephalans, including the Pacific spookfish (Rhinochimaera pacifica) and the brown chimaera (Chimaera carophila).
Status: Listed as Near Threatened on the IUCN Red List
Threats: Another result of lack of data means the threats to the prickly dogfish is also poorly understood. However, they are occasionally found in bottom trawls.