Habitat and Ecology
Information on the ecology and life history of the Graceful Shark is scant. The only available data are from the waters of northern Australia. The largest recorded size for this species is 167 cm from the Gulf of Thailand (Garrick 1982), while the largest size from Australian waters is 162 cm (Stevens and McLoughlin 1991). Males and females mature at 110-115 cm and probably mate each year. Litter size ranges from 1-9 pups, with a mean of three and the size at birth is 50-60 cm (Last and Stevens 1994). Mating probably occurs in February and ovulation in March or April. The gestation period is 9-10 months with parturition occurring in January and February (Stevens and McLoughlin 1991).
The Graceful Shark's diet is composed mostly of bony fishes. Stevens and McLoughlin (1991) reported fish from 91% of specimens with food in the stomach, while crustaceans occurred in 6% and cephalopods in 4%. In a study of predatory fish around Groote Eylandt in Australia's Gulf of Carpentaria, Brewer et al. (1995) reported that 88.5% of specimens with food in the stomach had consumed fish, 1.3% crabs and 8.5% cephalopods. Over 60% of the fish eaten were from the family Carangidae.
Depth range (m): 16 - 28
Depth range (m): 16 - 28
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.
Recorded at 50 meters.
Life History and Behavior
Molecular Biology and Genetics
Barcode data: Carcharhinus amblyrhynchoides
Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.
See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
-- end --
Download FASTA File
Statistics of barcoding coverage: Carcharhinus amblyrhynchoides
Public Records: 14
Specimens with Barcodes: 24
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
The Graceful Shark (Carcharhinus amblyrhynchoides) is a little-studied, coastal Indo-West Pacific species that is caught in commercial fisheries, but not as a targeted species. There is no evidence that this species faces a high extinction risk under the IUCN Criteria, but it has been impacted by fishing. Further research is required on its life history to aid in the assessment of this species.
Records of C. amblyrhynchoides catches in other countries are scant. Parry-Jones (1996) reported landings in China, and Keong (1996) reported their occurrence in fish markets in Thailand. Catches are probably also taken by commercial fisheries in India and Sri Lanka (Compagno 1984b). The Graceful Shark is exploited for its flesh and fins. There is no information available on the impact of fishing on C. amblyrhynchoides stocks.
Relevance to Humans and Ecosystems
The graceful shark or Queensland shark (Carcharhinus amblyrhynchoides) is a species of requiem shark, in the family Carcharhinidae, found in the tropical Indo-Pacific, from the Gulf of Aden to northern Australia. It is a midwater species that has been recorded to a depth of 50 m (160 ft). A stoutly built shark growing up to 1.7 m (5.6 ft) long, the graceful shark has a short, wedge-shaped snout, large, sickle-shaped pectoral fins and first dorsal fin, and black tips on most fins.
Graceful sharks prey mainly on bony fishes, and to a much lesser extent on cephalopods and crustaceans. It is viviparous, with females bearing litters of up to nine pups following a 9–10 month gestation period. Off northern Australia, birthing occurs in January and February, with mating shortly after. This species is potentially dangerous, but has not been implicated in any attacks. It is caught incidentally by commercial fisheries throughout its range for meat, fins, and liver oil, though specific information is lacking. The International Union for Conservation of Nature has listed it under Near Threatened.
Taxonomy and phylogeny
Australian ichthyologist Gilbert Percy Whitley originally described the graceful shark as Gillisqualus amblyrhynchoides, in a 1934 issue of Memoirs of the Queensland Museum. He based his account on a 60 cm (24 in)-long immature female caught off Cape Bowling Green in Queensland, hence the alternate common name Queensland shark. Later authors have synonymized Gillisqualus with Carcharhinus.
As with most Carcharhinus species, the evolutionary relationships of the graceful shark are poorly resolved. Based on morphology, Jack Garrick concluded in 1982 that its closest relative was the blacktip shark (C. limbatus), and that the two were closely related to the spinner shark (C. brevipinna). Leonard Compagno, in his 1988 phenetic study, also grouped those species together, along with the smoothtooth blacktip shark (C. leiodon) and the finetooth shark (C. isodon). However, molecular phylogenetic techniques have since found this interpretation to be invalid for the spinner, blacktip, and finetooth sharks.
Distribution and habitat
The graceful shark is distributed widely in the tropical Indo-Pacific, having been reported from the Gulf of Aden, southwestern India and Sri Lanka, the Gulf of Thailand, Vietnam, the Philippines to Borneo and Java, and Papua New Guinea to northern Australia from Townsville to Eighty Mile Beach. Given its rarity and the difficulty in distinguishing it from related species, its range is probably continuous and wider than the present patchy records suggest. The graceful shark is an open-water inhabitant that can be found from close to shore to the outer continental and insular shelves, diving at least 50 m (160 ft) down.
Contrary to its common name, the graceful shark's spindle-shaped body has been described as "tubby". The wedge-like snout is short and pointed. The eyes are rather large and circular, and equipped with nictitating membranes (protective third eyelids). The mouth has short, indistinct furrows at the corners and contains 31–33 upper and 29–33 lower tooth rows. The upper teeth have a single narrow cusp with serrated edges, upright at the center of the jaw and becoming more oblique on the sides. The lower teeth are similar to the upper teeth, but more upright and slender. The five pairs of gill slits are fairly long.
The pectoral fins are falcate (sickle-shaped) and taper to pointed tips; their leading margins measure about a fifth as long as the total length in sharks over 80 cm (31 in) long. The first dorsal fin is high and broad, with a pointed apex and a concave trailing margin; its origin lies roughly over the insertion (the rear of the fin base) of the pectoral fins. The second dorsal fin is relatively large and located about opposite the anal fin, which is about of equal size. There is no ridge between the dorsal fins. The caudal fin has a well-developed lower lobe and a ventral notch near the tip of the upper lobe. This species is bronze above and white below, which extends onto the flanks as a pale stripe. The pectoral fins, dorsal fins, lower caudal fin lobe, and sometimes the pelvic fins usually have black tips, while the upper caudal fin lobe darkens towards the trailing edge and the anal fin may be completely light. The fin markings tend to fade with age. The maximum known length is 1.7 m (5.6 ft).
Biology and ecology
The graceful shark feeds predominantly on bony fishes, with cephalopods and crustaceans being of minor importance. Jacks make up over 60% of its fish diet in the Gulf of Carpentaria. Like other members of its family, this species is viviparous: once the developing embryos exhaust their supply of yolk, the depleted yolk sac is converted into a placental connection to the mother. Off northern Australia, males and females likely mate every year in February, with ovulation following shortly after. Females typically bear litters of three, though individuals gestating up to nine pups have been reported. The young are born in January or February, following a gestation period of 9–10 months. Sexual maturity is attained at a length of 1.1–1.2 m (3.6–3.9 ft) for both sexes. A known parasite of this species is a tapeworm in the genus Cathetocephalus.
Given its size, the graceful shark is potentially dangerous to humans, though no attacks have been recorded. It is caught incidentally by commercial fisheries in Thailand, India, Sri Lanka, and probably elsewhere, using gillnets and longlines. It is a minor component of shark catches off northern Australia, comprising around 1.5% and 0.2% of all sharks caught in gillnets and on longlines, respectively, in the mid-1980s. Catches in the region have declined from historical highs in the 1970s and 1980s due to the departure of foreign fishing vessels following new gillnet regulations. The meat is sold fresh or dried and salted, the fins are shipped to East Asia for shark fin soup, and the liver is processed for vitamins. The International Union for Conservation of Nature has assessed this species as Near Threatened, noting more biological and fishery information is needed.
- Simpfendorfer, C. (2005). "Carcharhinus amblychynchoides". IUCN Red List of Threatened Species. Version 2010.1. International Union for Conservation of Nature. Retrieved April 30, 2010.
- Whitley, G.P. (June 30, 1934). "Notes on some Australian sharks". Memoirs of the Queensland Museum 10 (4): 180–200.
- Compagno, L.J.V. (1984). Sharks of the World: An Annotated and Illustrated Catalogue of Shark Species Known to Date. Food and Agricultural Organization. pp. 458–459. ISBN 92-5-101384-5.
- Garrick, J.A.f. (1982). Sharks of the genus Carcharhinus. NOAA Technical Report, NMFS Circ. 445: 1–194.
- Compagno, L.J.V. (1988). Sharks of the Order Carcharhiniformes. Princeton University Press. pp. 319–320. ISBN 0-691-08453-X.
- Naylor, G.J.P. (1992). "The phylogenetic relationships among requiem and hammerhead sharks: inferring phylogeny when thousands of equally most parsimonious trees result". Cladistics 8 (4): 295–318. doi:10.1111/j.1096-0031.1992.tb00073.x.
- Froese, Rainer and Pauly, Daniel, eds. (2010). "Carcharhinus amblyrhynchoides" in FishBase. April 2010 version.
- Last, P.R. and Stevens, J.D. (2009). Sharks and Rays of Australia (second ed.). Harvard University Press. pp. 269–270. ISBN 0-674-03411-2.
- Schmidt, G.D. and Beveridge, I. (June 1990). "Cathetocephalus australis n. sp. (Cestoidea: Cathetocephalidae) from Australia, with a Proposal for Cathetocephalidea n. ord". The Journal of Parasitology 76 (3): 337–339. doi:10.2307/3282661. JSTOR 3282661.