Bramble shark
A rare shark with spine-like dermal denticles and foul slimy skin that appears a metallic purple shine
The Bramble shark (Echinorhinus brucus) is a shark in the family Echinorhinidae. Aside from the eastern Pacific Ocean, it is found in tropical and temperate waters worldwide. They are rarely encountered, and swims close to the bottom of the seafloor, typically at depths of 656–2,953 feet. They may enter much shallower water, and some reports of even deeper waters. Water temperature plays a role, following cool thermoclines. The Bramble shark has a stout body with two small dorsal fins positioned far back and no anal fin. It has large, thorn-like dermal denticles scattered over its body, some of which may be fused together. It is purplish brown or black in color and grows up to 10 feet long. They also have a smelly mucus covering the skin. They may be high on the suction side of the RSI.
Family: Echinorhinidae – Bramble Sharks
Genus: Echinorhinus
Species: brucus
Phylum– Chordata
Class– Chondrichthyles
Subclass– Elasmobranchii
Common Name– Dogfish Sharks
Family– Echinorhinidae
Common Name– Bramble Sharks
Genus– Echinorhinus
Species– brucus
Status: IUCN Red List DATA DEFICIENT
Average Size and Length: The Bramble shark may reach just over 10 feet in length. Males on average are around 5 feet in length and females typically 6.6-7.2 feet.
Average Weight: The maximum weight on record is 440 pounds. It was a female 9.2 feet long.
Teeth and Jaw: The mouth of the Bramble shark is wide and curved, and has very short furrows at the corners. There are 20–26 upper and 22–26 lower tooth rows; each tooth is knife-like, with a single main cusp and up to 3 cusplets on either side.
Head: The Bramble shark has a somewhat flattened head. The snout is blunt and shorter than the width of the mouth, with widely spaced nostrils that are preceded by small skin flaps. The eyes do not have nictitating membranes and have tiny spiracles located well behind the eyes.
Denticles: The Bramble shark has white-colored dermal denticles that are scattered irregularly over the body and vary greatly in size, measuring up to 1.5 cm across. Each denticle is thorn-like in shape, with ridges radiating out from the central point over the base. As many as ten denticles may be fused together to form multi-pointed plates. The underside of the snout and the area around the mouth is densely covered by small denticles in sharks under 35 inches long; these denticles become larger and sparser in larger sharks.
The dermal denticles in near-term embryos are underdeveloped, appearing as minute spines located within open pits in the skin. To start, juveniles have close set denticles.
The dermal denticles are a big differentiator for the Bramble shark, and help one to recognize this species. In addition, the skin of the Bramble shark is covered by a layer of foul-smelling mucus several millimeters thick.
Tail: The caudal peduncle is robust and lacks notches at the caudal fin origins. The caudal fin is asymmetrical and has an indistinct lower lobe and an upper lobe without a notch in the trailing margin.
Demographic, Distribution, Habitat, Environment and Range: Bramble sharks are widely scattered in various locations in tropical and temperate waters worldwide. Most reports have come from the eastern Atlantic, Mediterranean and western Indo-Pacific Oceans, where its range extends from the North Sea and the British Isles to southern Mozambique. In the western Atlantic, reports have come from Louisiana, North Carolina, Massachusetts, Brazil, Argentina and Tobago. In the Indo-Pacific, the Bramble shark has been found from Oman, India, southern Japan, southern Australia, New Zealand, and possibly Kiribati.
Bramble sharks are found close to the sea floor. They typically inhabit continental and insular shelves and slopes at depths of 656–2,953 feet. However, they have been reported as shallow as 59 feet deep in areas with upwellings of cold water, and also as deep as almost 4,000 feet. In European waters, they may migrate into shallower depths of 66–656 feet deep during the summer.
Diet: Bramble sharks’ prey on smaller sharks, bony fishes, and crabs.
Ram-Suction Index: Bramble sharks may be high on the suction side of the RSI.
Aesthetic Identification: The Bramble shark has a thick, cylindrical body. There are five pairs of gill slits, with the fifth pair the longest. It is brown to black above, with an almost purple metallic shine. In one specimen caught, it was reported to have a greenish glow momentarily. They are counter-shaded paler below on the underside. Some sharks may have red or black splotches. The pectoral fins are short and angular, while the pelvic fins are long and relatively large. The dorsal fins are small, with the first dorsal fin origin lying behind the pelvic fin origins. There is no anal fin.
Biology and Reproduction: Bramble sharks are ovoviviparous with females producing litters of 15–52 pups. Females have two functional ovaries and two uteruses. Newly born pups have been estimated to measure 16–20 inches long. The size at sexual maturity is uncertain; the smallest known mature males and females are 4.9 feet and 6.9 feet long.
Behavioral Traits, Sensing and Intelligence: Unknown.
Speed: They are a slow-moving species.
Bramble Shark Future and Conservation: It is an occasional bycatch of commercial and recreational fishers, and may be used for fishmeal and liver oil. There isn’t enough data to determine status and conservation efforts. The population does seem to have declined over the last century.
Bramble Shark Recorded Attacks on Humans: Harmless to humans.