|Scientific Name:||Heterodontus galeatus|
|Species Authority:||(Günther, 1870)|
Cestracion galeatus Günther, 1870
|Taxonomic Source(s):||Eschmeyer, W.N., Fricke, R. and Van der Laan, R. (eds). 2016. Catalog of Fishes: genera, species, references. Updated 31 March 2016. Available at: http://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp. (Accessed: 31 March 2016).|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Kyne, P.M. & Bennett, M.B.|
|Reviewer(s):||Walls, R.H.L. & Huveneers, C.|
|Facilitator/Compiler(s):||Kyne, P.M. & Walls, R.H.L.|
The Crested Hornshark (Heterodontus galeatus) occurs in relatively shallow waters of the continental shelf (to a depth of 93 m) and is endemic to the eastern Australian states of Queensland and New South Wales. It is considered uncommon, particularly when compared with the sympatric Port Jackson Shark (H. portusjacksoni). Relatively little information is available on its life history. The species is not targeted commercially, and incidental capture, recreational fishing and protective beach meshing programs are not thought to be affecting the species. Post-release survivorship of Crested Bullhead Shark is expected to be high based on studies on the morphologically similar and closely-related H. portusjacksoni. Although uncommon, there are no current significant threats to the species, and it likely benefits from a network of marine protected areas across its range. It is therefore assessed as Least Concern.
|Previously published Red List assessments:|
|Range Description:||The Crested Hornshark is endemic to the western Pacific Ocean in warm temperate waters along the east coast of Australia ranging from Cape Moreton in southern Queensland south to Batemans Bay in New South Wales (Johnson 1999, Last and Stevens 2009). Whitley (1940) reports an egg case from Moa Island in the Torres Strait, but this northern Queensland record may be doubtful (J. Johnson, pers. comm. 2003).|
Native:Australia (New South Wales, Queensland)
|FAO Marine Fishing Areas:|
Pacific – southwest; Pacific – western central
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||No information is available on population size or structure. This species is considered uncommon, particularly when compared with the sympatric Port Jackson Shark (Heterodontus portusjacksoni). McLaughlin (1969) when assessing the heterodontid sharks of the central New South Wales (NSW) coast wrote that the Crested Hornshark is "difficult to find underwater and was rarely encountered by fishermen, indicting that its local density was probably much lower than that of H. portusjacksoni" (McLaughlin 1969, page 9).|
|Current Population Trend:||Unknown|
|Habitat and Ecology:||The Crested Hornshark tends to replace the Port Jackson Shark in northern New South Wales (NSW) and southern Queensland with the centre of its distribution in warmer waters than the Port Jackson Shark (Whitley 1940, McLaughlin 1969). This species is recorded from the intertidal zone to 93 m on the continental shelf (Whitley 1940, Michael 1993, Last and Stevens 2009). Some speculate that it may be more common in deeper waters than close inshore (Kuiter 1993, J. Johnson, pers. comm., 2003). The species is found around rocky reefs, among large macroalgae and on seagrass beds (Michael 1993). The Crested Hornshark does not appear to form large aggregations as displayed by the Port Jackson Shark. Individuals of both species can be observed together occupying the same habitat (D. Powter, pers. comm., 2003). |
Various maximum sizes of the Crested Hornshark have been reported. Stead (1963, page 19) states that "as a general rule it [H. galeatus] is found of a somewhat smaller size than the common Port Jackson shark [H. portusjacksoni] of similar age". The Port Jackson Shark is reported to grow to a maximum of 165 cm total length (TL) but is "normally much smaller" (Last and Stevens 2009, page 119). Whitley (1940) reported a total length (TL) of 120 cm for the Crested Hornshark. Last and Stevens (2009) report the species attaining 130 cm TL, Michael (1993) reports 150 cm TL, and observations on the NSW central coast suggest a maximum size of at least 150 cm TL (D. Powter, pers. comm. 2003).
Last and Stevens (2009) report that females mature at about 70 cm TL and males at about 60 cm TL. However, there have been observations of two males from southern Queensland of 53.5 and 56 cm TL, which were sexually mature (Kyne 2008). The reported size of maturity for females may be based on a single captive individual hatched and held at the Taronga Park Aquarium, Sydney, Australia (Whitley 1950). This individual is reported to have matured in its eleventh year of age, based on the first time it laid eggs in captivity (Whitley 1950). Oviposition is reported to take place during July and August at depths of 20-30 m (McLaughlin 1969, Last and Stevens 2009). Michael (1993) reports egg-laying at depths of 15 m or more, also during late winter, but states that oviposition can occur all year around. There are also reports of egg cases attached to sponges in waters as shallow as 8.6 m (D. Powter, pers. comm., 2003). The Crested Hornshark generally lays in deeper water than the Port Jackson Shark, which mostly lays in less than 5 m (McLaughlin and O’Gower 1971). Young are reported to hatch at about 22 cm TL (Last and Stevens 2009). The individual hatched in captivity at the Taronga Park Aquarium was reported at a smaller size of about 17 cm TL (Jacups 1943, Whitley 1950).
There are minimal reports on the egg-laying rate and hence annual fecundity of the species. McLaughlin (1969) examined one mature female (77.5 cm TL) in June, and found it to be consistent with an estimated fecundity for the Port Jackson Shark of 10-16 eggs per year (Powter and Gladstone (2008) have more recently confirmed an ovarian fecundity of 16 for the Port Jackson Shark). Reproductive periodicity has not been documented for the Crested Hornshark. The Port Jackson Shark displays an annual reproductive cycle (McLaughlin and O’Gower 1971) so the Crested Hornshark may be similar. Whitley (1940) suggested a gestation period of at least five months while others report a longer period of 8-9 months (Jacups 1943, Whitley 1950, Last and Stevens 2009). This latter figure may be based on the one captive individual held at the Taronga Park Aquarium. There is no information available on age and growth of wild Crested Hornsharks; however, limited information is available from captivity. Jacups (1943) and Whitley (1950) report a growth rate of 5 cm per year for the captive Taronga Park female. It is thought that the species is relatively long-lived given its apparent protracted immaturity (Whitley 1950).
|Use and Trade:||Not known to be utilized.|
This species is not targeted or marketed commercially (Last and Stevens 2009, N. Otway, pers. comm. 2003). Recreational fishing is thought to have little effect on the species because of its apparent rarity in inshore waters. Spearfishers are more likely to encounter the Port Jackson Shark on inshore reefs, and they are known to take this species for sport. Line fishers may encounter the Crested Hornshark on rare occasions. The species is caught as bycatch in various commercial fisheries operating in New South Wales and southern Queensland waters. It is taken as bycatch in demersal prawn trawl fisheries in New South Wales (Ocean Prawn Trawl Fishery) and in Queensland (eastern king prawn sector of the East Coast Trawl Fishery) (Kyne 2008). The New South Wales ocean trap and line fishery is also likely to capture this species, however numbers taken as bycatch are not known as there is no distinction between the recording of the two heterodontid species in fishery statistics (H. galeatus and H. portusjacksoni; Nick Otway, pers. comm., 2003). Heterodontus species captured as bycatch in this fishery are normally released alive (N. Otway, pers. comm. 2003). There is a small annual bycatch in the South East Trawl Fishery, although catches are grouped with the Port Jackson Shark, and 100% of the catch is discarded (Walker and Gason 2007).
Protective beach meshing programs operate in New South Wales and Queensland waters and are likely to capture the Crested Hornshark. Numbers caught in Queensland are not available while catches in the New South Wales Protective Beach Meshing Program are not divisional between the two heterodontid species (N. Otway, pers. comm. 2003). Between October 1972 and December 1990, 435 Port Jackson Sharks were caught in this program, equating to a catch rate of 0.394 sharks/km of net/year (Krogh 1994), although these figures are considered as underestimates. Krogh (1994) notes that the Port Jackson Shark, being the more common species, is more likely to constitute the larger portion of the catch. Reid and Krogh (1992) provide information on net mortality for Heterodontus spp. caught in the program. Of 60 individuals sampled, 96.7% were alive from the net, the highest survival rate of the 11 species or species groups sampled. Non-dangerous sharks are released by contractors servicing the protective nets whenever practical (Reid and Krogh 1992). Given this survivorship, and if animals are successfully released alive, then beach meshing may not be having a significant effect on Heterodontus species. Similarly, if animals are successfully released alive from commercial fishing gear including trawlers, then these activities may also be having minimal effect. Studies have been done on the morphologically similar and closely-related Port Jackson Shark, and these studies suggest high post-release survivorship.
Small individuals of the closely-related Port Jackson Shark are captured for use in the hobbyist aquarium trade, and it is possible that Crested Hornhark is also collected for the aquarium trade. Port Jackson Shark fetch good prices, with those advertised by aquarium suppliers in the US being sold up to US$180. Live animals are sold both domestically and internationally. Specimens are also collected by commercial aquaria for display purposes, but in relatively small numbers. Large commercial aquariums are able to successfully breed Port Jackson Sharks in captivity, reducing the reliance on wild caught animals.
|Conservation Actions:||The Crested Hornshark is likely to occur in a number of marine protected areas including Queensland's Moreton Bay Marine Park at the northern extent of the species' range, and several marine parks in New South Wales. Zoning plans for these parks are complex and ‘no-take’ zones only exist in small areas (for example, recreational line and spear fishing are permitted in many of these parks). Marine Protected Areas in New South Wales waters where the Crested Hornshark is likely to occur and where commercial and recreational fishing activities are completely banned in at least some sections of the park include the Solitary Islands Marine Park (71,000 hectares), Jervis Bay Marine Park (21,450 hectares) and the Cape Byron Marine Park (~22,000 hectares). Additionally, the Crested Hornshark is likely to occur in the Commonwealth managed Solitary Islands Marine Reserve (17,000 hectares) adjacent to New South Wales’ Solitary Islands Marine Park.|
|Citation:||Kyne, P.M. & Bennett, M.B. 2016. Heterodontus galeatus. The IUCN Red List of Threatened Species 2016: e.T41824A68625634.Downloaded on 27 September 2016.|
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