Brownbanded Bamboo Shark: Chiloscyllium punctatum

Family: Hemiscylliidae
Common name(s)

Brownbanded Bamboo Shark, Grey Carpetshark (IUCN).

Identification

Slender shark with a rounded snout. Snout length roughly equal to mouth width. Long barbells extend from nasal openings beyond mouth level. Spiracle slightly smaller than, and positioned below and slightly behind eye. Short gill slits. Gill slit margins are noticeably pale. A lateral groove on each flank runs from behind head to base of tail. Dorsal fins have concave posterior margins. First dorsal origin over pelvic fin insertion. Second dorsal almost as large as first. Anal fin rounded; positioned directly before lower caudal lobe. Caudal fin thin, with a long, rounded upper post-ventral margin, and a square terminal margin.
Dorsal coloration tan or greyish-brown with subtle darker bands. Bands may be absent in older adults. Neonates and small juveniles are strikingly patterned with bold, light and dark brown bands.

Size

Maximum size 132cm. Size at birth less than 13-18cm.

Habitat

Tropical coral or rocky reefs, intertidal pools, sand and mud flats, and seagrass beds.  From the intertidal zone to at least 85m.

Distribution

From the east coast of India eastwards, throughout southeast Asia including southern Japan and northern Australia.

Conservation Status

NEAR THREATENED

The brownbanded bamboo shark is fished and retained throughout Southeast Asia. In particular, it is one of the most common species found in fish markets across Thailand, where overall catch landings of sharks have declined by >90% from 10,000 tons to 1,000 tons in less than a decade (2004–2011). It is susceptible to capture in a range of fishing gear, and given its coastal preference, the distribution for this species largely overlaps with artisanal and commercial fisheries in many countries. Within Australia, the species is afforded protection through marine park zones throughout several parts of its distribution; it is not targeted for any fishery and as bycatch it is largely released with likely high survival rates given its general hardiness. There may be some level of take for the aquarium trade.
There is some taxonomic uncertainty for this species with evidence suggesting that the Australian form may be a cryptic sister-species to the Southeast Asian form. This taxonomic uncertainty has implications for the conservation of this species as this may limit the replenishment of exploited populations if they do not receive recruitment from largely unexploited populations. Based on the ongoing threats to this species from fishing pressure, habitat destruction and suspected population declines based on declines in aggregate Thai shark landings, the Grey Carpetshark is assessed globally as NEAR THREATENED. In Southeast Asia where the fishing pressure is greatest and increasing, it may meet VULNERABLE in the near future as it is likely to be close to meeting the thresholds for criterion A2bd. A key priority is to clarify population reduction and population substructure.

In Australia, where mortality from fisheries is limited, and the species is common in some marine protected areas, the species is assessed as Least Concern.

Citation

Dudgeon, C.L., Bennett, M.B. & Kyne, P.M. 2016. Chiloscyllium punctatumThe IUCN Red List of Threatened Species 2016: e.T41872A68616745. https://dx.doi.org/10.2305/IUCN.UK.2016-1.RLTS.T41872A68616745.en. Downloaded on 29 December 2020.

Reproduction

Oviparous. In captivity, brownbanded bamboo sharks laid between 115 and 152 eggs each year. One captive female stored sperm for 45 months before fertilization.

Diet

Feeds on small bony fishes, crustaceans, and other invertebrates.

Behavior

Nocturnal. Rests by day in crevices on the reef or under corals.

Reaction to divers

Easy to approach with slow casual movements. Will bolt if molested.

Diving logistics

Brownbanded bamboo sharks occur throughout most of southeast Asia but they are virtually guaranteed at numerous dive sites near Brisbane and the Gold Coast in Australia. Shag Rock and the Scottish Prince shipwreck are both wellknown spots where divers may see a dozen or more on a single dive.

I have also encountered them in the Gulf of Thailand, and at sites around Malapascua Island in the Philippines.

Similar species

Grey Bamboo Shark An extremely similar species. Distinguished by smaller size, less distinct white edging on gill openings, straighter posterior margins of dorsal fins, and no banding at all on adults.