There is taxonomic uncertainty for this species with molecular data suggesting it is a species complex with the Australian and eastern Indian Ocean forms possibly separate cryptic sister-species to the Southeast Asian forms (Naylor et al. 2012, Fahmi et al. 2021a).

The Grey Carpetshark (Chiloscyllium punctatum) is a small (to 148 cm total length) shark with a broad range across the Indo-West Pacific Oceans from southwest India to Australia and north to Japan. It occurs in shallow coastal waters to a depth of 85 m in a wide variety of habitats including soft substrates, mangroves, and coral reefs. The species is extremely hardy and can survive out of water for several hours. It is a species complex that consists of four separate genetic populations that may be separate species though further taxonomic work is needed. The species is caught incidentally in a range of artisanal and industrial gears including demersal trawl, longline, and gillnet. It is subject to intense and largely unmanaged fisheries across its Southeast Asia range and is retained for food (although it is of low-medium value) often in high numbers. Fishing pressure is intense across the range of this species, yet it is still commonly landed in parts of its range; it is the most abundantly caught shark in Thailand and Malaysia. It appears to have significantly declined in Indonesia, though quantifying the decline is difficult. There are no long-term trend data on the populations; general long-term shark population trends across Southeast Asia have shown declines of 37–99% over the past three generation lengths (30 years). The relative proportion of bamboosharks (Chiloscyllium spp.) in shark landings has increased significantly in Southeast Asia over recent decades in the region, which may be in response to the overfishing of large sharks resulting in meso-predator release of this species. It is a relatively productive species and has not declined to the extent that other species have in the region. In Australia, mortality is minimal and managed and the population is suspected to have been stable over the past three generation lengths (30 years). It is suspected that the Grey Carpetshark has undergone a population reduction of 20–29% over the last three generation lengths (30 years) based on actual levels of exploitation, and it is assessed as Near Threatened (nearly meeting Vulnerable A2d). When the taxonomy is fully resolved, this assessment should be revisited.

The Grey Carpetshark is widely distributed within the Indo-West Pacific Oceans occurring from southwest India to Australia and north to Japan (Ebert et al. 2021). It is uncertain whether the Grey Carpetshark occurs in the Western Indian Ocean where it has been reported as incidental catch from fish markets from the Arabian Sea and adjacent waters (Paighambari and Daliri 2012). Extensive surveys in the Western Indian Ocean region by researchers have not collected species conforming to Grey Carpetshark, suggesting either misidentification in earlier reports or that the species has become rare (K.V. Akhilesh pers. comm. 2023). Since the previous published assessment (Dudgeon et al. 2016), the distribution map has been updated to show occurrence within the known bathymetric limits.

The Grey Carpetshark appears to be a species complex with genetic work across the Indo-Australian region suggesting there are four operational taxonomic units (OTUs): Indonesia-Malaysia archipelago, west coast of Sumatra, Lesser Sunda Island region, and Australian-Papua New Guinea with the Australian-Papua New Guinea OTU a potential cryptic species (Fahmi et al. 2021a, Fahmi et al. 2021b). There is some genetic population structure within the Indonesia-Malaysia OTU across and within jurisdictions (Fahmi et al. 2021b, Lim et al. 2021). Further supporting work investigating morphological, biological, and ecological differentiators is required to determine if the OTUs represent separate species (Fahmi et al. 2021a).

This species is one of the most common sharks caught in coastal fisheries across Southeast Asia (Fahmi et al. 2021c). During 2015–2016, the Grey Carpetshark was the most abundant shark recorded at landing sites across six countries: Myanmar, Thailand, Cambodia, Viet Nam, Malaysia, and Indonesia with the most individuals landed in Thailand (2,584), followed by Malaysia (1,506), Cambodia (710), and Viet Nam (160) with only 16 landed in Indonesia and four in Myanmar (SEAFDEC 2020). In Thailand, it accounts for up to 65% of the commercial fisheries shark catches in the Andaman Sea (Arunrugstichai et al. 2018). This is despite previous dramatic declines in total shark landings in Thailand from 2004–2011 which were inferred to indicate population reductions in Grey Carpetshark of >90% over three generation lengths (30 years; Dudgeon et al. 2016). In Malaysia, it accounts for 32–60% of the commercial fisheries shark landings on the west coast of Peninsular Malaysia and also dominates landings on the east coast of Peninsular Malaysia and Sabah (Arai and Azri 2019, Fahmi et al. 2021b, Lim et al. 2021).

In Indonesia, this species was the most dominant of the orectolobiformes (carpet sharks) landed during Java Sea surveys from 2001–2006 accounting for 78% by number (848 individuals) of orectolobiformes (Dharmadi et al. 2015). The dramatic decline to only 16 individuals observed in 2015–2016 is of concern, with no landings observed at Cilacap (Java) which was surveyed in 2001–2006 and all 16 individuals at Lampulo (North Sumatra) which was not surveyed in 2001–2006 (SEAFDEC 2020). Regular enumeration data in Lampulo also recorded the species in low numbers (Fahmi; Wildlife Conservation Society unpub. data). However, direct comparisons between the two survey periods is confounded by the possibility there are two different OTUs and that fishing effort is significantly higher in the Java Sea than in Cilicap and Lampulo. Monthly observation of the gillnet fishery in Jakarta Bay showed no sign of a decline in the catch of the Grey Carpetshark during surveys from 2016–2018. Monitoring in East Kalimantan waters from 2016–2021 showed a fluctuation in abundance of the Grey Carpetshark with a declining trend from 2017–2020, followed by an increase in 2021 (Fahmi unpub. data). Bamboo sharks (Chiloscyllium spp.) are caught only as incidental catch in the south coast Java waters (including Cilacap); they are rarely caught in the longline fishery as incidental catch. Finally, daily monitoring in Lombok from 2015–2021 showed a fluctuation in the number of catches of the species without any sign of decline (62–104 individuals per year) (Fahmi; based on Indonesia Institute of Science, Ministry of Marine Affairs and Fisheries, and Wildlife Conservation Society unpub. data). Extensive trawling in the Arafura Sea (Blaber et al. 2005) and in the Java Sea (Blaber et al. 2009) is likely to have previously impacted 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 had a large impact on the Grey Carpetshark.

A stock status assessment of trawl caught Grey Carpetshark across three landing sites (Songkhla-Thailand, Sihanoukville-Cambodia, and Kota Kinabalu-Sabah-Malaysia) estimated the species was being sustainably fished in Sabah but it could not tolerate any further increase in fishing mortality in Thailand and Cambodia (Pattarapongpan et al. 2021). This may be due to the relatively lower catches of the species in Kota Kinabalu where the fishing grounds are further offshore (8 nautical miles, nm) compared to ~5 nm in the other two countries (Pattarapongpan et al. 2021).

Monitoring of fish landing sites in Southeast Asia have shown that the relative proportion of bamboo sharks (Chiloscyllium spp.) in shark landings has increased significantly over recent decades due to declines in large sharks and retention of the remaining smaller species (Lam and Sadovy de Mitcheson 2011, Lack and Sant 2012, Arunrugstichai et al. 2018). This general trend has been seen across fish stocks across the region where smaller-sized fish are being landed as a result of fishing down the ecosystem; a consequence of intensive fishing that changes the size composition of the catch (e.g., China; Pauly and Liang 2019). General trends in shark catches in Thailand and in reconstructed catches of sharks and rays across Southeast Asia from 1950–2014 indicate population declines of 37–99% when scaled to three generation lengths (30 years) of the Grey Carpetshark (see Kyne et al. 2021b assessment for Whitespotted Bambooshark (Chiloscyllium plagiosum).

In Australia, the species is common, particularly in some locations, such as reef flats in the Capricorn-Bunker group, Great Barrier Reef and in Moreton Bay, Queensland. It can be seen in groups of up to a dozen individuals at specific locations that provide habitat protection in otherwise open environments. Mortality from fisheries is limited and it has significant refuge from fisheries in both marine parks and in areas that are unfished or lightly fished (Kyne et al. 2021a). An Australian national Red List assessment noted that in Australia, the population trend is suspected to be stable and it was assessed as Least Concern (Kyne et al. 2021a).

In summary, the relative proportion of bamboosharks in shark landings has increased significantly over recent decades in Southeast Asia and the Grey Carpetshark may have benefited from meso-predator release due to the overfishing of large sharks (Kyne et al. 2021b). However, the fishing pressure across its Southeast Asia range is intense and general long-term shark population trends have shown declines of 37–99% over the past three generation lengths (30 years). This species is still very abundant in many parts of its range; it is a relatively productive species, therefore it has not declined to the extent that other species have in the region. In Australia, mortality is minimal and managed and the population is suspected to be stable. Overall, it is suspected that the Grey Carpetshark has undergone a population reduction of 20–29% over the past three generation lengths (30 years) based on actual levels of exploitation.

The Grey Carpetshark is demersal on the continental shelf to a depth of at least 85 m (Ebert et al. 2021). It occurs in a variety of habitats including nearshore intertidal and subtidal habitats, over sandy and muddy substrates, seagrass, mangroves, and rocky and coral reefs (Fahmi et al. 2021a). 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), and it can survive out of water for up to half a day (Chapman et al. 2011, Ebert et al. 2021). It reaches a maximum size of at least 132 cm total length (TL) in Australia and up to 148 cm TL in Indonesia-Malaysia (Weigmann 2016, Fahmi et al. 2021a, Fahmi unpub. data). Size-at-maturity in Malaysia and Indonesia is smaller than in Australia; males mature at 63–65 cm TL (Indonesia; Dharmadi et al. 2015, Fahmi et al. 2021c), 68–76 cm TL (Malaysia: Yano et al. 2005), and 82 cm TL (Australia; Last and Stevens 2009). Females mature at 70 cm TL (Indonesia, Fahmi et al. 2021d) and 87 cm TL (Australia; Last and Stevens 2009). Reproduction is oviparous and year-round with captive aquaria females laying large numbers of egg cases, for example, 692 egg cases were laid in one year between six females (Mooloolaba, Queensland, Australia; Harahush et al. 2007). The number of egg cases per year varies markedly and incubation periods differed between aquaria ranging from 92 days (Phuket, Thailand; Yano et al. 2005) to 153 days (Mooloolaba, Queensland, Australia; Harahush et al. 2007). Size-at-birth is 13–18 cm TL (Ebert et al. 2021). Female age-at-maturity in Indonesia is 6.6 years and maximum age is 13.5 years; generation length is therefore 10 years (Fahmi et al. 2021d).

The Grey Carpetshark is a common target and incidental catch of trawl, gillnet, longline, and handline industrial and artisanal fisheries across Southeast Asia and is retained mainly for its meat (Dharmadi et al. 2015). It is released in some areas, such as occasionally in Malaysian artisanal fisheries where although generally all catch is retained, sometimes bamboo sharks (Chiloscyllium spp.) are selectively released (Lim et al. 2021). This is a robust species able to survive out of water for a few hours and thus, post-release survival is likely to be high.

Across Southeast Asia, there is substantial and generally unregulated and unmanaged fishing pressure. India has an intensive fishing fleet of trawlers and gillnetters and this species is occasionally landed as incidental catch of the commercial shrimp trawl fisheries along the Tamil Nadu and Andrha Pradesh coast and is consumed fresh locally (K.K. Bineesh unpub. data). In Thailand, most fisheries in Thailand are overexploited, particularly in the Gulf of Thailand (Derrick et al. 2017). In Indonesia, fishing effort in archipelagic waters is intense and across all sectors has been increasing since 1950s with steep increases in effort since the 1980s (Tull 2014). Indonesia has the largest chondrichthyan fishery globally, and reports substantial catches of target and non-target chondrichthyans (White et al. 2006). It has been among the top shark fishing nations for over 20 years (Oakes and Sant 2019). Within the Indonesia-Malaysia archipelago (relevant for the operational taxonomic unit), the threats to this species are high due to the intensive trawl fisheries (Fahmi et al. 2021a). However, on the west coast of Sumatra and in the Lesser Sunda Island region, the habitat precludes demersal trawling thus reducing fishing pressure; it would still be caught in demersal longline fisheries but these are not as intensive as trawl fisheries in the wider Indonesia-Malaysia region (Fahmi et al. 2021a). Coastal fisheries in Cambodia are considered overexploited and in Viet Nam, most marine stocks have been declining since the 1990s and are now considered fully or over-exploited (Teh et al. 2014a, Teh et al. 2014b). In China, inshore coastal fisheries resources have been depleted since the 1980s, following intensive demersal trawling and net fisheries during the preceding 30 years (Yu and Yu 2008, Liang and Pauly 2017). Since 1989, the catch-per-unit effort of fish stocks across China has steadily decreased and large, highly valued species have been replaced by small, less valuable species, with most of the catch now used as feed in aquaculture (MacKinnon et al. 2012).

In Papua New Guinea, the fishing pressure is relatively minor and this species is commonly caught in the Gulf of Papua Prawn Trawl Fishery where it accounts for 3.7% of the shark and ray catch; it is assessed with medium risk from the fishery, mainly based on a relatively high susceptibility to capture in the fishery (Baje et al. 2021). It is also taken in small-scale coastal fisheries in some areas (White et al. 2017). In Australia, the threats are minimal and managed; the Grey Carpetshark is caught incidentally in trawl and net fisheries and released as shark and ray retention is prohibited in trawl fisheries and it is of low commercial value. The species is caught in the Commonwealth Northern Prawn Fishery where it accounted for 1.6% of the shark and ray catch and it is considered at low risk of overfishing due to estimated fishing mortality being below levels leading to population reduction (Stobutzki et al. 2000, Zhou and Griffiths 2008). The mandated use of bycatch reduction devices including Turtle Excluder Devices significantly reduced the catch of this species (Brewer et al. 2004). It also has significant refuge in the marine park network and in considerable areas of its range that are either unfished or lightly fished (Kyne et al. 2021).

Indirect and sublethal sources of mortality include habitat destruction and degradation, and pollution (e.g., heavy metals) (Heileman and Tang 2009, Heileman 2009, MacKinnon et al. 2012). In both the East and South China Seas, reclamation has contributed to a dramatic reduction in coastal and mangrove wetlands. There has been a loss of 70% of mangroves in the last 70 years in the South China Sea, as well as modifications to about 50% of seagrass beds and degradation of significant areas of coral reef habitat (Heileman and Tang 2009, Heileman 2009). In Viet Nam, dynamite and cyanide fishing, and sedimentation have caused widespread destruction of coral reefs (Jameson et al. 1995, FAO 2020).

This species has a low-medium economic value and is used for local consumption of its meat and is exported fresh and frozen in Southeast Asia with Singapore the largest market. Fins are consumed mainly locally in some areas though there is also some export (White et al. 2006, Dharmadi et al. 2015, Fahmi et al. 2021c). The fins have been reported in the Hong Kong fin trade where they represented 0.29% of fins sampled (Cardeñosa et al. 2020). The species is displayed and bred in aquaria (Last et al. 2010, Dharmadi et al. 2015).

There are no specific conservation measures for this species. There are many general management measures that contribute to conserving this species in several range states. Marine Protected Areas that incorporate >20 km of coral reef can provide significant protections where the species has fidelity to reefs (Dwyer et al. 2020). Marine Protected Areas are common in coral reef areas throughout its range, but only those that are sufficiently large and well enforced provide refuge (MacNeil et al. 2020). 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 which are well-enforced. While fishing is still allowed in most areas of the parks, the species is not targeted and is likely to survive capture and release from incidental catch due to its general hardiness. Further research is needed on taxonomy, population size and trends, and life history, and catch rates should be monitored. Once the taxonomy is fully resolved, this assessment should be revisited.