|Scientific Name:||Chiloscyllium punctatum Müller & Henle, 1838|
|Taxonomic Source(s):||Eschmeyer, W.N., Fricke, R. and Van der Laan, R. (eds). 2016. Catalog of Fishes: genera, species, references. Updated 2 May 2016. Available at: http://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp. (Accessed: 2 May 2016).|
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Assessor(s):||Dudgeon, C.L., Bennett, M.B. & Kyne, P.M.|
|Reviewer(s):||Lawson, J. & Dulvy, N.K.|
|Facilitator/Compiler(s):||Kyne, P.M., Walls, R.H.L., Simpfendorfer, C. & Chin, A.|
The Grey Carpetshark (Chiloscyllium punctatum) is a widely distributed (Indo-West Pacific region) and potentially fecund (oviparous) tropical species occurring in a variety of habitats throughout its range.
This species 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.
|Previously published Red List assessments:|
|Range Description:||The Grey Carpetshark is widely distributed within the Indo-West Pacific in tropical and warm-temperate waters occurring in a variety of habitats throughout its range. It is known from India, Southeast Asia, Japan, southern New Guinea and northern Australia (Last and Stevens 2009, Akhilesh et al. 2014). It is uncertain whether the Grey Carpetshark occurs in the Western Indian Ocean where it has been reported as bycatch from fish markets from the Persian Gulf (Paighambari and Daliri 2012). There is taxonomic uncertainty for this species with evidence suggesting that the Australian form may be a cryptic sister-species to the Southeast Asian form (Naylor et al. 2012).|
Native:Australia (Northern Territory, Queensland, Western Australia); Cambodia; China; India; Indonesia; Japan; Malaysia; Papua New Guinea; Philippines; Singapore; Taiwan, Province of China; Thailand; Timor-Leste; Viet Nam
|FAO Marine Fishing Areas:|
Indian Ocean – western; Indian Ocean – eastern; Pacific – western central; Pacific – northwest; Pacific – southwest
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Little is known of Grey Carpetshark population structure or trends in the wild. It has been reported in large numbers at fish markets in Thailand (Compagno 2001, Krajangdara 2014), although is less frequently observed by SCUBA divers as reported from Thailand (1% sighting rate based on >4,400 dives; Thailand eShark Project 2015) and Indonesia (Erdmann, pers. comm. 2015). |
In Australia, it is commonly encountered at various locations, such as reef flats in the Capricorn-Bunker group, Great Barrier Reef and in Moreton Bay, Queensland. It can been seen in groups of up to a dozen individuals at specific locations that provide protection/cover in otherwise open environments.
|Current Population Trend:||Decreasing|
|Habitat and Ecology:||The Grey Carpetshark is found in a variety of habitats including nearshore intertidal and subtidal habitats, over sandy and muddy substrates, seagrass beds and rocky and coral reef habitat to depths of 85 m (White and Potter 2004, Last and Stevens 2009, Chin et al. 2012). The species is extremely hardy and physiologically adapted to inhabiting environments that undergo cyclical hypoxic conditions (e.g., coral reef flats; Chapman and Renshaw 2011). Small individuals hide in crevices and among coral and are well camouflaged with their broad banding pattern.|
The Grey Carpetshark is an oviparous species. Sperm storage occurs with one captive female shark storing sperm for 45 months before producing offspring (Bernal et al. 2015). Captive aquaria females lay large numbers of eggs with 466 eggs laid during one year for 3 females (Phuket, Thailand; Yano et al. 2005) and 692 eggs laid in one year between six females (Mooloolaba, Queensland, Australia; Harahush et al. 2007). The number of eggs per year varies markedly demonstrating potential variation in fecundity due to external conditions with only 21.4% of eggs producing hatchlings (Harahush et al. 2007). The Grey Carpetshark has demonstrated a clear seasonal mating and egg laying period in captivity in Queensland, Australia (Harahush et al. 2007). Incubation periods differed between aquaria with hatching occurring after 92 days (Phuket, Thailand; Yano et al. 2005) and 153 days (Mooloolaba, Queensland, Australia; Harahush et al. 2007). The differences may be due to higher ambient water temperatures in the Thai aquaria or may also reflect population level differences (Dharmadi et al. 2015).
Eggs hatch between 13 and 18 cm total length (TL; Last and Stevens 2009). Compagno (2001) reports size at maturity for males at 68 to 76 cm TL, and females at about 63 cm TL. Similar male sizes at maturity were reported from Malaysia (68-76 cm TL; Yano et al. 2005) and Indonesia (65–66 cm TL; Dharmadi et al. 2015). Last and Stevens (2009) report male size of maturity at 82 cm TL for Grey Carpetshark from Australia. This shark attains a maximum adult size of at least 132 cm TL (Last and Stevens 2009). Species-specific age and growth information is not available for the Grey Carpetshark. A congeneric, the Whitespotted Bambooshark (C. plagiosum), demonstrates an age at maturity of 4.5 years and maximum known age in the wild of 12.5 years (but captive age of 25 years; Chen et al. 2007), resulting in a generation length of 8.55 years. Captive Grey Carpetshark are known to at least 16 years of age (Harahush et al. 2007), and using the age at maturity of Whitespotted Bambooshark, a generation length of 9.5 years is estimated for the Grey Carpetshark.
|Generation Length (years):||9.5|
|Use and Trade:||
This species is a commonly caught inshore species for meat and other products and is also displayed and bred in aquaria (Dharmadi et al. 2015).
The Grey Carpetshark is widely fished across most of its range outside of northern Australia. It comprises one of the most commonly landed shark species at Thai fishing ports where capture is primarily through otter trawls and also pair trawls. Aggregate shark landings have decreased from ~10,000 tons in 2004 to ~1,000 tons in 2011 (Krajandara 2014). Assuming these declining landings are indicative of overfishing-induced declines and are indicative of population reduction of this species they represent a >90% population reduction within a three generation span (~28.5 years). Declines are likely to have also occurred elsewhere. This species was the most common of all the orectolobiform sharks (comprising 77.9%) landed in Indonesia during surveys from April 2001-March 2006. Landings were recorded from Jakarta, Bali and Lombok fish markets from trawl, handline, longline and gillnet fisheries (Dharmadi et al. 2015). Genetic analyses (DNA barcoding) of shark fins collected during market surveys conducted across Indonesia from mid 2012 to mid 2014 found the vast majority of landed species were pelagic sharks with common reef and carpet sharks extremely rare. Given the extensive shallow coastal habitat around Indonesia that would support the reef and carpet shark species, the authors conclude that this is a strong indication of the collapse of reef shark populations in Indonesia, most likely due to overfishing (Semibiring et al. 2015).
Extensive trawling in the Arafura Sea (Blaber et al. 2005) and in the Java Sea (Blaber et al. 2009) is likely to impact the Grey Carpetshark in these regions. Documented large declines in shark and ray catches associated with corresponding increases in fishing effort in the Java Sea (Blaber et al. 2009) is likely to have a large impact on the Grey Carpetshark in Indonesian waters and may be representative of fishing impacts across the region.
A prawn trawl fishery consisting of about nine vessels operates in the Gulf of Papua in southern Papua New Guinea and the Grey Carpetshark is caught in the Gulf of Papua in moderate numbers (W. White, pers. comm. 2015).
Within Australia, small numbers of the Grey Carpetshark are captured in the Pilbara Trawl (Western Australian Department of Fisheries 2010), the Queensland East Coast Inshore Finfish Fisheries (Harry et al. 2011), the Queensland East Coast Trawl Fishery (Kyne 2010), the Northern Prawn Fishery (Stobutzki et al. 2002) and most certainly other fisheries in northern Australia. Carpetsharks are generally discarded in Australian fisheries.
The species is protected in a significant proportion of its Australian range on the east coast of Australia in the Great Barrier Reef Marine Park and the Moreton Bay Marine Park. While fishing is still allowed in most areas of the parks, the species is not targeted and is likely to survive capture as bycatch due to its general hardiness.
Re-stocking of wild populations from captive bred aquaria stock (Phuket Marine Biological Centre) has occurred on one occasion in Phuket, Thailand which comprised the release of 99 captive bred sharks between 6-12 months old on 02 December 2004, marking the birthday of HM King Bhumibol Adulyedej (Phuket Gazette 2004).
The Gulf of Papua prawn trawl fishery is managed under national Papua New Guinean laws and regulations, and there are some seasonal closures in place; although bycatch reduction devices are not currently in place, there are plans to implement in the near future (L. Baje, National Fisheries Authority, pers. comm. 2015).
|Citation:||Dudgeon, C.L., Bennett, M.B. & Kyne, P.M. 2016. Chiloscyllium punctatum. The IUCN Red List of Threatened Species 2016: e.T41872A68616745.Downloaded on 21 September 2017.|