Taxon name
Chiloscyllium griseum
Müller & Henle, 1838
Uploaded by
National Red List Database
Taxonomic information
Scientific name
Chiloscyllium griseum
Müller & Henle, 1838
Assessed taxon level
Species
Higher level taxonomic groupings
Vertebrates
Fishes
Species authority
Müller & Henle, 1838
Location and scope
Specific locality or subnational name or regional name
United Arab Emirates (the)
Scope (of the Assessment)
National
Countries included within the scope of the assessment
United Arab Emirates (the)
Does the assessment cover a marine EEZ area(s)?
Not_assigned
Conservation Status
Assessed as
Near Threatened
Qualifying criteria (if given)
A2cd
Criteria system used
IUCN
(see Assessment details)
Assessment rationale/justification
The Grey Bamboo Shark occurs throughout UAE coastal waters, but it is poorly known in part due to taxonomic uncertainty and confusion with Chiloscyllium arabicum. It is not targeted, but is taken as bycatch in trawl (and other) fisheries, and is typically discarded due to its small size and low market value. It is especially susceptible to exploitation (target and bycatch) in many largely unregulated gill net, longline and trawl fisheries that operate within its range outside and surrounding UAE waters. Some management measures are now in place in the Arabian Sea region, although domestic fisheries are likely to continue. Though data specifically from the UAE are not available, individuals in the UAE are a component of a larger, interconnected and migratory population that occurs broadly in the north-western Indian Ocean. It is inferred that declines reported in the Arabian Sea region are representative of its status in the UAE. Based on recorded levels of exploitation and decline in habitat quality, it is suspected to have declined by 20-30% over the past three generation lengths, or about 27 years. It is listed as Near Threatened, nearly meeting the thresholds for Vulnerable A2cd.
Assessment details
Assessors/contributors/reviewers listed
UAE National Red List Workshop
Criteria system used
IUCN
Reference for methods given
IUCN. 2012. IUCN Red List Categories and Criteria: Version 3.1, Second edition. IUCN, Gland, Switzerland and Cambridge, UK. iv + 32pp pp. And IUCN. 2012. Guidelines for Application of IUCN Red List Criteria at Regional and National Levels: Version 4.0. Gland, Switzerland and Cambridge, UK: IUCN. iii + 41pp.
Further information
Endemism (according to assessment)
Endemic to region
Not assigned
Taxon distribution as listed in assessment
The Grey Bamboo Shark occurs throughout UAE waters. In the Arabian Seas region, it is known from a few specimens from the Arabian Gulf, Iran, Pakistan, India and Sri Lanka. Its global distribution is uncertain due to confusion with other species, but is known to occur in the Indo-West Pacific.
Is there a map available in assessment?
Yes
Habitat and systems
Ecological system type
Habitat
Habitat details as listed in assessment
This species is a sluggish inshore bottom dweller found on sandy and muddy bottoms, on rocks and in coral lagoons at depths from 5 to 100 m (Weigmann 2016). It is oviparous and deposits eggs in small oval egg cases on the sea floor. The maximum size is at least 77 cm total length (TL). Free-living individuals have been found at sizes of at least 12.2 cm, and size at hatching uncertain. Males mature between 45 and 55 cm TL. The species feeds mainly on small fish, shrimps, worms, molluscs and crabs. Age data are not available, but generation length is estimated as 9 years using data from the similar-sized White-spotted Bambooshark (C. plagiosum) (Chen et al. 2007).
Threats and conservation measures listed
Threats listed in assessment
In the UAE, sharks have been impacted by targeted commercial fisheries until 2014 when a ban on export of sharks was imposed (Ministry of Climate Change and Environment). Sharks continue to be impacted by artisanal and bycatch fisheries (Annual Fisheries Statistical Report for Abu Dhabi Emirate 2001-2018), though catch data are not species-specific. This species is impacted by bycatch fisheries that are active elsewhere in its range. Marine habitats in the Gulf are experiencing high levels of disturbance and quickly deteriorating due to major impacts from development activities (including dredging and reclamation), desalination plants, industrial activities, habitat destruction through the removal of shallow productive areas and major shipping lanes (Sheppard et al. 2010). Corals in the UAE and Arabian Gulf have severely declined due to the increasing frequency of mass bleaching events caused by rising water temperatures, which is a consequence of climate change, as well as pervasive coastal development (Riegl et al. 2018, Burt et al. 2019).
Publication
Ralph, G.M., Stump, E., Linardich, C., Bullock, R.W., Carpenter, K.E., Allen D.J., Hilton-Taylor, C., Al Mheiri, R., and Alshamsi, O. 2021. UAE National Red List of Marine Species: Reef-building corals, cartilaginous fishes and select bony fishes. 2021. Ministry of Climate Change and Environment, Dubai, United Arab Emirates.