|Scientific Name:||Pristiophorus cirratus|
|Species Authority:||(Latham, 1794)|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Walker, T.I. & Simpfendorfer, C. (SSG Australia & Oceania Regional Workshop, March 2003)|
|Reviewer(s):||Shark Specialist Group Australia & Oceania Regional Group (Shark Red List Authority)|
The 2000 IUCN Red List Assessment classed this species as Near Threatened. The current assessment lowers the classification to Least Concern due to new information, including a comprehensive study of age, growth and reproduction. The revised assessment is also based on a 25-year time series of catch and effort data from the Southern Shark Fishery and 12 years of monitoring data from an onboard observer program on trawlers.
Pristiophorus cirratus is a moderately abundant endemic species on the continental shelf and, to a lesser extent, the continental slope of southern Australia. The species is harvested over its entire range, but most of the catch is taken from Bass Strait in gillnets of mesh-size ranging 6 to 6½ inches or from New South Wales and off eastern Victoria by the South East Trawl Fishery. Current exploitation rates are considered sustainable. Classification of this species is based mainly on six pieces of evidence:
(1) stable commercial catch rates for the combined catch of P. nudipinnis and P. cirratus during the past 20 years, following an earlier decline;
(2) fishery-independent survey indicates over the past 25-year period indicates the number of animals caught declined to 67%; the change is not statistically significant;
(3) fishing effort has been reducing and a combined Total Allowable Catch has been implemented for P. nudipinnis and P. cirratus;
(4) relatively high biological productivity; maximum age of 15 years with 6 to 19 offspring produced biennially;
(5) no contraction of range or fragmentation of the population, and;
(6) the three-mile closure of all Victorian waters to shark fishing provides a large refuge for the species.
|Range Description:||P. cirratus is endemic to the waters of southern Australia's outer continental shelf. Last and Stevens (1994) considered that the distribution was poorly defined, but most likely to be between Jurien Bay in Western Australia and Eden in New South Wales, including Tasmania. Compagno (1984) reported a possible occurrence in the Philippines. The recorded depth range is 40 to 310 m (Last and Stevens 1994). The highest concentrations are in Bass Strait (Walker et al. 2002).|
Native:Australia (New South Wales, South Australia, Victoria, Western Australia)
|FAO Marine Fishing Areas:||
Indian Ocean – eastern; Pacific – southwest
|Range Map:||Click here to open the map viewer and explore range.|
|Habitat and Ecology:||
P. cirratus is a small, slightly dorso-ventrally compressed, shark with a long rostrum (snout), narrow and tapering with numerous lateral rostral teeth. Paired elongated barbels originate from the ventral side of the rostrum and the second dorsal fin is nearly as large as the first. The upper body is pale yellow to greyish brown with distinctive dark markings incorporating spots and wide bands. Detailed descriptions can be found in Compagno (1984a) and Last and Stevens (1994). Sawsharks can be distinguished from the morphologically similar sawfishes by lateral (as opposed to ventral) gill slits and the presence of barbels originating from the rostrum.
Maximum total length and maximum total body mass are higher for females (149 cm, 8.5 kg) than for males (132 cm, 3.5 kg). Ageing studies indicate that the species has a maximum life span of 15 years and hence has comparatively high productivity among chondrichthyans. The species exhibits aplacental viviparity and produces 6 to 19 offspring biennially, and the young are born at approximately 38 cm total length. Total length at which 50% of the females matured is 107 cm. The diet consists of mainly small teleosts and, to a lesser extent, crustaceans (T.I. Walker, unpublished data).
One threat to the population of P. cirratus is their capture as byproduct from targeting Mustelus antarcticus with gillnets of 6-6½-inch mesh-size off South Australia (Walker 1999), Victoria and Tasmania. During 1970-01 the catch of P. cirratus and Pristiophorus nudipinnis combined from the Southern Shark Fishery varied 43-301 tonnes (carcass weight), 7% of the total catch of all shark species (Walker et al. 2002).
Another threat is their capture as byproduct in the South East Trawl Fishery, which targets a range of quota teleost species with demersal trawl nets off New South Wales, eastern Victoria and eastern Tasmania. The sawshark catch from this sector was 106 tonnes during 2002.
In addition, small quantities of P. cirratus are taken by the Great Australia Bight Trawl Fishery. The catch from this sector was 28 tonnes during 2002.
Minor threats include gillnets in the shark fishery of Western Australia and fishing with long-lines and other methods.
In Bass Strait, observed catch rates from research vessels during 1973 to 1976 and from scientific observations on board commercial vessels during 1998-01 indicate that the number of animals per thousand km-hours in bottom-set gillnets of six-inch mesh-size declined from 381 to 292. This is a decline to 67% of former levels over a 25-year period. (Walker et al. in press). Catch per unit effort reported by commercial fishers over this same period declined from 15.32 to 7.71 kg per km-lift for P. nudipinnis and P. cirratus combined; i.e., a decline to 50% of former levels. The decline in the commercial catch rate for these species occurred during 1974 to 1982 and catch rates subsequently stabilized during 1983 to 2001. A steady decline in fishing effort since the mid 1980s and adoption of a Total Allowable Catch during 2002 for P. cirratus and P. nudipinnis jointly are expected to help secure the stocks of these species. There is negligible targeting of P. cirratus; most of the catch of these species is taken as byproduct to targeting Mustelus antarcticus.
|Conservation Actions:||In the Australian Southern Shark Fishery, P. cirratus has been harvested as byproduct or bycatch to the targeting of Galeorhinus galeus and Mustelus antarcticus in oceanic waters since the mid-1920s and possibly earlier in inshore areas. Baited hooks attached to bottom-set longlines was the principal fishing method until the early 1970s when the method was replaced by bottom-set gillnets. Management measures in this fishery include limited entry for the use of gillnets and longlines (since 1984) and, for all fishing sectors, Total Allowable Catches (TAC) (for P. cirratus and P. nudipinnis combined) (since 2002). Input controls include limits on length of net (since 1988), various 4 to 6 week closed seasons to protect pregnant animals of Galeorhinus galeus during October to December (1953 to 1967 and 1993 to 1994), and a legal minimum mesh-size of six inches for gillnets (since 1975) for most of the fished area. During 2002, the TAC for P. cirratus and P. nudipinnis was 191 tonnes for the Southern Shark Fishery, 124 tonnes for the South East Trawl Fishery, and 31 tonnes for the Great Australia Bight Trawl Fishery. The three-mile closure of all Victorian waters to shark fishing provides a large refuge for the species.|
|Citation:||Walker, T.I. & Simpfendorfer, C. (SSG Australia & Oceania Regional Workshop, March 2003) 2003. Pristiophorus cirratus. The IUCN Red List of Threatened Species. Version 2015.2. <www.iucnredlist.org>. Downloaded on 02 July 2015.|