The Blind shark (Brachaelurus waddi) is one of two species of Blind sharks belonging to the family Brachaeluridae. The can be found along the coast of eastern Australia, this nocturnal, bottom-dwelling species is common in rocky areas and seagrass beds from the intertidal zone to a depth of 460 feet. It often roams in tidal pools where it may be trapped by the receding tide, and can survive for an extended period out of water. The Blind shark is not actually blind; its common name came from its habit of closing its eyes when taken out of the water. Their eyes are fully functioning.
Family: Brachaeluridae – Blind Sharks
Genus: Brachaelurus
Species: waddi
Phylum– Chordata
Class– Chondrichthyles
Common Name– Carpet Sharks
Family– Brachaeluridae
Common Name– Blind Sharks
Genus– Brachaelurus
Species– waddi
Status: IUCN Red List LEAST CONCERN
Average Size and Length: They are born around 17 cm/ 6.7 inches. Mature males have been measured under 60 cm/ 1.9 feet. Mature females have been measured under 66 cm/ 2.2 feet. The maximum recorded has been 120 cm/ 3.9 feet.
Current Rare Mythical Sightings: Blind shark fossils have been found in Late Cretaceous period (99.6–65.5 Ma) deposits from Europe, as well as in Pliocene epoch (5.3–2.6 Ma) deposits from Chile and Peru. The Wobbegongs are a close sister taxon.
German naturalists Marcus Elieser Bloch and Johann Gottlob Schneider originally described the Blind shark as Squalus waddi, in their 1801 Systema Ichthyologiae. However, there is uncertainty over whether their account was referring to this species or the Brownbanded Bamboo shark (Chiloscyllium punctatum), as it was based on a painting by John Latham that could not be located by subsequent authors. In 1907, James Douglas Ogilby coined the genus Brachaelurus for this species, from the Greek brachys meaning “short”, and ailouros meaning “cat”. In 1973, Leonard Compagno placed it and the Bluegrey carpetshark in their own family. It may also be referred to as the Brown catshark or Dusky dogfish.
Teeth and Jaw: The mouth is small. There are 32–34 upper tooth rows and 21–29 lower tooth rows. Each tooth has an upright, awl-shaped central cusp and a pair of lateral cusplets. Their jaws are quite strong.
Head: Its head is wide, flattened, and blunt with small eyes on top. The nostrils are placed almost at the tip of the snout. There are nasoral and circumnarial groves. There are long tapering barbels underneith. The mouth is in front of the eyes. The eyes are small and oval and there are large oval spiracles behind and below the eyes. There are strong ridges underneath. The rims are raised.
Denticles: The dermal denticles are large, giving the skin a rough texture.
Tail: The caudal fin comprises about a quarter of the total length, with no ventral lobe and a strong ventral notch near the tip of the upper lobe.
Demographic, Distribution, Habitat, Environment and Range: The Blind shark can be found in east Australia from Mooloolaba in southern Queensland to Jervis Bay in New South Wales (11°S – 36°S, 112°E – 143°E). Past reports from off the coast of western Australia and the northern territory appear to be misidentifications of the Brownbanded Bamboo shark. They can be found on rocky shores in tidepools, reefs and seagrass beds anywhere between 0-460 feet. It may be trapped by the receding tide, and can survive for an extended period out of water Juveniles have been found in high-energy surge zones. In Nelson Bay, the Blind shark has been observed lying in the open atop sponges. They prefer tropical temperatures.
Diet: They feed on small fish, crustaceans, squid and sea anemones.
Ram-Suction Index: They are high on the suction index. Prey is captured by sucking it into their mouths with a powerful suction force.
Aesthetic Identification: The Blind shark is brown with white spots dorsally. The young have dark saddles that are obsolete in adults. They are light yellowish ventrally. The shark is small and stout. The five pairs of gill slits are small, with the fifth pair close to the fourth. The dorsal fins are similar in size and have rounded apices and angular free rear tips. They are set far back on the shark. The origin of the first dorsal fin is over the pelvic fin bases. The second is well in front of the origin of the anal fin. The anal fin and lower caudal fins are so close that they almost touch. The anal fin is less than half the size of the dorsal fins. The pectoral fins are large and broad, with rounded margins. The pelvic fins are rounded and almost as large as the pectoral fins.
Biology and Reproduction: The Blind shark is ovoviviparous. They have anywhere from 7-8 pups per litter in November.
They can survive for extended periods out of water; approximately 18 hours.
Their eyes are fully functional. Their eyes are closed when they are out of water; it retracts its eyeballs and shuts its thick lower eyelids.
They have lived 20 years in captivity.
A known parasite of this shark is an undescribed species of tapeworm in the genus Carpobothrium.
Behavioral Traits, Sensing and Intelligence: The Blind shark is nocturnal. They hide in caves under ledges during the day, and actively feed at night.
Speed: It is sluggish by day.
Blind Shark Future and Conservation: They are of least concern. They are relatively common and collected for aquaria. They are not of commercial value so rarely taken by fisheries because of their strong anemone taste. They are very hardy and easily survive releases well. The Blind shark has even been induced to breed in captivity, with the Sydney Aquarium having successfully maintained a breeding colony.
It is caught incidentally by prawn trawl and other fisheries off Queensland and New South Wales, though post-discard survival may be high due to its ability to tolerate being out of water. Small numbers of blind sharks are caught by recreational fishers, who regard them as a nuisance because its small mouth and strong jaws make removing lodged hooks difficult.
Blind Shark Recorded Attacks on Humans: They are not a threat to humans, but it can bite if provoked and is difficult to remove, owing to its strong jaws and powerful suction. There are cases of Blind sharks biting and holding onto divers’ wetsuits even after they surfaced, and could only be removed by prying open their jaws.