|Scientific Name:||Neotrygon kuhlii|
|Species Authority:||(Müller & Henle, 1841)|
Dasyatis kuhlii (Müller & Henle, 1841)
Trygon kuhlii Müller & Henle, 1841
|Taxonomic Notes:||Investigation is vital to resolve the taxonomic issues associated with this species complex and make full assessments of its status. There may be more than five species involved in total. There are multiple colour morphs within the range which may represent different species. For example, two forms of N. kuhlii in Indonesia (i.e., the Java form and the Bali form) are probably separate species based on morphological and molecular evidence, which is surprising given how close these areas are geographically (W. White pers. obs. 2007).|
|Red List Category & Criteria:||Data Deficient ver 3.1|
|Assessor(s):||Fahmi, White, W.T. & Jacobsen, I.P.|
|Reviewer(s):||Simpfendorfer, C. & Kyne, P.M.|
|Facilitator/Compiler(s):||Kyne, P.M., Walls, R.H.L., Simpfendorfer, C. & Chin, A.|
The Bluespotted Maskray (Neotrygon kuhlii) is reported throughout a wide range in the Indo-Pacific region, but may be a species-complex of more than five species. Investigation is vital to resolve the taxonomic issues associated with this species-complex and due to this taxonomic uncertainty it is not possible to assess the species beyond Data Deficient at present. The Bluespotted Maskray species-complex is extensively exploited in parts of its range, and is often abundant in Asian fish market landings. A relatively small stingray (to 47 cm disc width), it is likely more resilient to exploitation than larger inshore batoids, but overall management of catches is lacking across most of its range. It is a common bycatch of Australian prawn trawl fisheries where it is discarded. Information is generally required on catch rates and rates of fishing mortality across its range; the significance of this may be dependent on the taxonomic status of the species-complex as some species may be found to have restricted occurrences. It is also exhibited in some public aquariums, but does not constitute a major species in aquarium trade. Further work is required to identify the species involved and make full assessments of their status.
|Previously published Red List assessments:|
|Range Description:||The Bluespotted Maskray is an apparently wide ranging species found from the western Indian Ocean to the eastern Pacific Ocean. However, research including fish market surveys (e.g., White and Dharmadi 2007) and genetic analyses (Ward et al. 2008) has identified a number of variants. Accordingly, the Bluespotted Maskray is believed to be a species-complex with current estimates suggesting there may be up to five different species (W. White, pers. obs.). Taxonomic investigation will be vital to identify the species involved and their true distributions. This species-complex has been reported from American Samoa, Australia, Cambodia, Cook Islands, Guam, China (Hong Kong), Taiwan, India, Indonesia, Japan, Ogasawara Islands, Madagascar, Malaysia, Mauritius, Micronesia, Mozambique, Myanmar, Marianas, New Caledonia, Palau, Papa New Guinea, Philippines, Samoa, Somalia, South Africa, Sri Lanka, Tanzania, Thailand, Tonga, Vanuatu, Viet Nam and Yemen (Compagno 1986).|
Native:American Samoa (American Samoa); Australia (New South Wales, Northern Territory, Queensland, Western Australia); Cambodia; China; Cook Islands (Cook Is.); Guam; Hong Kong; India; Indonesia; Japan (Ogasawara-shoto); Madagascar; Malaysia; Mauritius; Micronesia, Federated States of ; Mozambique; Myanmar (Myanmar (mainland)); New Caledonia; Northern Mariana Islands; Palau; Papua New Guinea; Philippines; Samoa; Somalia; South Africa; Sri Lanka; Taiwan, Province of China; Tanzania, United Republic of; Thailand; Tonga; Vanuatu; Viet Nam; Yemen
|FAO Marine Fishing Areas:|
Indian Ocean – western; Indian Ocean – eastern; Pacific – western central; Pacific – northwest; Pacific – eastern central; Pacific – southwest
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The population size of the Bluespotted Maskray is unknown. In Indonesia, market observations were conducted at several landing sites in Java and Kalimantan from 2005, and showed that the species is quite common. They were recorded at almost all landing sites (fishing areas including the Java Sea, off southern Java (Indian Ocean), Sunda Strait, Karimata Strait, Makassar Strait, West Kalimantan, Natuna Islands) (White and Dharmadi, pers. obs., 2007). Extensive surveys of various fish landings sites in eastern Indonesia, conducted between April 2001 and March 2006 recorded a total of 28,385 individual batoids, comprising 54 species belonging to 12 families. The Java form of the Bluespotted Maskray contributed 42.7% by number to the total number of batoids recorded but only 3.9% by biomass. The Bali form of the Bluespotted Maskray contributed 3.4% by number to the total number of batoids recorded but only 0.7% by biomass (White and Dharmadi 2007).|
In Australia, the Bluespotted Maskray is considered to be relatively common on the eastern, northern and western coasts. It is abundant in some inshore environments and coastal inlets and bays such as Moreton Bay in southeast Queensland.
Information on the population, abundance and distribution of the species throughout the remainder it the range is generally limited and/or often fragmented.
|Current Population Trend:||Unknown|
|Habitat and Ecology:||The Bluespotted Maskray is a demersal species found in a broad range of habitats including sandy and muddy bottoms, and rocky and coral reefs, from the intertidal zone to a depth of 90 m (White et al. 2006, Last and Stevens 2009). |
Size parameters differ between regions and areas because this is most likely a complex of several species. The Java (Indonesia) form attains at least 38 cm disc width (DW), with males maturing at 22-26 cm DW and females at 23-27 cm DW (White et al. 2006, White and Dharmadi 2007). Size at birth for the Java form is 11-16 cm (White et al. 2006). The Bali (Indonesia) form attains at least 45 cm DW, with males maturing at 31-35 cm DW (White et al. 2006, White and Dharmadi 2007). Size at birth for the Bali form is ~17 cm DW. Reproduction is viviparous, with histotrophy. Java and Bali forms give birth to litters of 1-2 pups after an unknown gestation period and there is apparently no reproductive synchronicity (White et al. 2006).
Research into the life-history parameters of Australian Bluespotted Maskray (Jacobsen and Bennett 2009, Peirce et al. 2009) suggests that they attain similar sizes to the Indonesian specimens. In Australia, females reach at least 46.5 cm DW; males attain at least 38.1 cm DW. Size at first sexual maturity for males and females is 24.9 cm DW and 26.3 cm DW, respectively. Size at 50% sexual maturity was marginally higher: males, 29.4 cm DW; females, 31.4 cm DW. Litter size is 1-3 pups and size at birth is 11.7-17.0 cm DW (Jacobsen and Bennett 2009, Pierce et al. 2009). Age and growth patterns for this species have been validated (Pierce and Bennett 2009) with females reaching at least 17 years and males 15 years (Jacobsen and Bennett 2009).
|Use and Trade:||The Bluespotted Maskray is utilized extensively across parts of its range, particularly in Southeast Asia, for example it is exploited heavily in Indonesia where it is retained for commercial sale and consumption. There is is utilized for its meat but it is of limited value due to its small size. The meat is often smoked and salted or dried for marketing locally. It will on occasion be retained by aquarium fish collectors for private and public display.|
The Bluespotted Maskray is exploited heavily across parts of its range, particularly in Southeast Asia, for commercial sale or consumption. It is often a commonly observed catch in Asian fish markets, such as in Indonesia and Taiwan.
In Indonesia, this species is caught as utilized bycatch in trawl, trammel net and Danish seine fisheries targeting mixed demersal fishes. It is commonly caught in large numbers by trawl and Danish seine boats operating in the Java Sea. This species is the second most important elasmobranch caught by the Danish seine fishery according to the total catch (biomass) and is the principle elasmobranch in terms of the total number of individuals (contributing ~ 700 kg/boat in average) (Fahmi pers. obs. 2007). According to anecdotal observations of artisanal fisheries catches in Java between August 2006 and May 2007 (inclusive), the production of Bluespotted Maskray increased from 231 kg/boat (in August 2006) to 724 kg/boat (in May 2007). Total production of rays in Indonesian fishery statistics also showed an increasing trend (DGCF 2005). This is a relatively small ray which is likely to be more resilient to depletion in fisheries than some of the other larger ray species in parts of its known range.
In Australia, the Bluespotted Maskray is caught and subsequently discarded as bycatch in a number of Australian prawn trawl fisheries including the East Coast Trawl Fishery (Queensland), the Torres Strait Prawn Fishery and the Northern Prawn Fishery (northern Australia) (Stobutzki et al. 2002, Salini et al. 2007, Kyne 2008, Jacobsen et al. 2010). The introduction of bycatch reduction devices (BRDs) and turtle exclusion devices (TEDs) may help to minimize the negative effects of prawn trawling on local populations. However, it is a relatively small elasmobranch and the benefits of using a TED will be less than that observed for larger species (Brewer et. al. 2006). The primary reason for this is that smaller rays are more likely to pass through the bars of a TED and into the codend of the prawn trawl net. This problem is compounded by the fact that prawn-trawl mortality rates tend to be higher for smaller species (Stobutzki et al. 2002). Outside of the prawn trawl industry, the Bluespotted Maskray is caught in some inshore net fisheries with a very low number being retained for commercial sale. The species is retained by aquarium fish collectors to sell commercially or for use in private collections. Retention rates in Australia though are expected to be low for this species.
Where the Bluespotted Maskray occurs off the southern coast of Papua New Guinea it has the potential to interact with the local prawn trawl and net fisheries. It has previously been reported from Naru (W. White, pers. obs.) but was not observed in recent bycatch surveys involving the Gulf of Papua Trawl Fishery (L. Baje, National Fisheries Authority, pers. comm., 2015). Despite this, it is possible that this species interacts with this fishery.
|Conservation Actions:||There are no species-specific conservation measures in place for the Bluespotted Maskray, although the species would derive some benefit from broader management initiatives including spatial/temporal closures and the use of bycatch reduction devices in Australian prawn trawl fisheries. Information on the catch rate of this species and post-release mortality rates tends to be limited and requires further investigation. This problem will be exacerbated in areas like Indonesia and New Guinea where (a) catch rates and catch compositions are poorly defined, and (b) management initiatives are less developed.|
|Citation:||Fahmi, White, W.T. & Jacobsen, I.P. 2015. Neotrygon kuhlii. The IUCN Red List of Threatened Species 2015: e.T161590A68636167.Downloaded on 28 October 2016.|
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