|Scientific Name:||Callorhinchus milii Bory de Saint-Vincent, 1823|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Walker, T.I., Francis, M.P. & Reardon, M.B.|
|Reviewer(s):||Simpfendorfer, C., Dulvy, N.K. & Kyne, P.M.|
|Facilitator/Compiler(s):||Kyne, P.M., Walls, R.H.L., Simpfendorfer, C. & Chin, A.|
The Elephant Fish (Callorhinchus milii) is a moderately abundant holocephalan species endemic to the continental shelf of each of southern Australia and New Zealand. The species has medium biological productivity; although maximum age is in the range 9–20 years, it matures relatively early with females laying ~20 eggs annually. In southern Australia, the species is exploited over its entire range, but most of the catch is taken from Bass Strait by gillnets of mesh-size ranging 6–6½ inches, from southern New South Wales and eastern Victoria by demersal otter trawl and Danish seine, and the Great Australian Bight by demersal otter trawl. Current exploitation rates are considered sustainable. Ongoing commercial catch per unit effort from shark gillnet fishing has been stable since 1981, following an earlier decline. Fishing effort and catch have reduced with implementation of a Total Allowable Catch for Elephant Fish since 2002. In addition to these specific measures a series of general protections are in place reducing effort on this species, including (1) a three-mile closure of all Victorian waters to shark gillnet fishing provides a large refuge for the species; and (2) a prohibition of demersal otter trawl and Danish seining, and in some areas all other fishing methods, in extensive Commonwealth marine reserves. In New Zealand, TACs first implemented in 1986 subsequently led to increasing catch per unit effort. The fishery is stable with the population likely to be above the biomass required to provide the maximum sustainable yield. On the basis of the stable populations and active management of this species it is assessed as Least Concern
|Previously published Red List assessments:|
|Range Description:||The Elephant Fish is distributed off southern Australia from Esperance in Western Australia (longitude ~121°54´E) to about Sydney in New South Wales (latitude ~34°S), including Tasmania (Last and Stevens 2009). The species is also distributed around New Zealand.|
Native:Australia (New South Wales, South Australia, Tasmania, Victoria, Western Australia); New Zealand (North Is., South Is.)
|FAO Marine Fishing Areas:|
Indian Ocean – eastern; Pacific – southwest
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||For this assessment it is assumed that a single genetic stock occurs in southern Australia and a separate single genetic stock in New Zealand, with no mixing between the two stocks.|
Catch per unit effort as reported by commercial fishers (where catch refers to carcass mass, i.e. headed, eviscerated and fins removed), peaked at 2.1–3.5 kg per km-lift during 1974–79, but subsequently declined to below half these levels and stabilized at 0.8–1.1 kg per km-lift (Walker and Gason 2009). There is also an annual assessment of this species that uses catch rates from the Australian gillnet fishery. Standardized catch rates have been variable since 1980. From 2005 to 2009 catch rates increased rapidly, however, catch rates have since dropped back to levels closer to the long term average in the fishery (Morison et al. 2012).
In Australia, the species is most abundant in Bass Strait and during the egg-laying period enters large estuaries and bays, such as American River, Kangaroo Island and parts of the west coast in South Australia, and Westernport Bay, Port Phillip Bay and Barwon River estuary in Victoria. In New Zealand it is most abundant on the east coast of the South Island.
|Current Population Trend:||Stable|
|Habitat and Ecology:||The Elephant Fish occurs from inshore to depths of more than 200 m (Last and Stevens 2009), but 99% of the catch by shark gillnets is taken at depths less than 80 m (Walker and Gason 2009). This species is oviparous, laying egg pairs in shallow water that may take up to 10 months to hatch (Last and Stevens 2009). It is a seasonal breeder with females moving to shallower habitats to lay eggs (Francis 1997, Last and Stevens 2009). Eggs are laid over several weeks each year. Juveniles remain in the shallow habitats for up to 3 years, which may make them vulnerable to trawl capture in New Zealand (Francis 1997). Males and females are often caught separately by fishers and hence appear to be segregated most of the year. The Elephant Fish has medium biological productivity (Morison et al. 2012). Size at which 50% of the animals are mature is 59 cm fork length (FL) for females and 54 cm FL for males, and mature females lay an average of 19.7 eggs per year (Bell 2012). Maximum age is estimated at 11 years in New Zealand (Francis 1997) and 16 years in southern Australia (Brown et al. 2000) from tag release-recapture, at 9 or 20 years in southern Australia depending on method from sectioning dorsal-fin spines (Bell 2012), and at 5–8 years for males and 8–9 years for females in New Zealand from analysis of length-frequency composition of catches (Francis 1997).|
|Use and Trade:||The Elephant Fish is caught both commercially and recreationally in southern Australia and New Zealand. The flesh is of good quality and sold in seafood markets as whitefish fillets (Last and Stevens 2009). Off southern Australia, the Elephant Fish is common and taken as byproduct in the Shark Gillnet Sector and Commonwealth Trawl Sector of the Southern and Eastern Scalefish and Shark Fishery; the species is rarely targeted other than by recreational fishers, often discarded, and taken mainly off Victoria in Bass Strait.|
In southern Australia, Elephant Fish have been retained by fishers as byproduct to the targeting of School Shark (Galeorhinus galeus) and Gummy Shark (Mustelus antarcticus) in continental shelf 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. Elephant Fish are captured with gillnets of 6–6½" mesh-size off Victoria and Tasmania, but only small quantities are caught off Western Australia and South Australia. Since 1970, the catch of Elephant Fish from the Shark Gillnet Sector varied 4–118 tonnes (carcass mass) (Walker and Gason 2009). Some targeting of females occurs inshore by recreational fishers during the egg-laying period. For fishing methods other than shark gillnetting in the Southern and Eastern Scalefish and Shark Fishery, mean annual catch during the 7-year period 2000–06 estimated by combining monitoring data from scientific on-board observers and mandatory catch and effort returns submitted by commercial fishing operators was 48 t whole mass of which 94% was retained for marketing and 6% discarded. Most of this catch was taken off southern New South Wales and eastern Victoria by demersal otter trawl (12%) and Danish seine (85%), and in the Great Australian Bight (3%) (Walker and Gason 2007). The recreational catch mass by recreational fishers in Westernport Bay of Victoria was estimated at 45 t, carcass mass, during 2008 (Braccini et al. 2009).
In New Zealand, the species is most abundant off the east coast of the South Island. The fishery appears to be stable with populations likely to be above the biomass required to provide the maximum sustainable yield (Annala et al. 2002, Coakley 1971, 1973, Gorman 1963, McClatchie and Lester 1994).
In southern Australia, management measures in the Southern and Eastern Scalefish and Shark Fishery include limited entry for the use of gillnets and longlines (since 1984) and Total Allowable Catches (TAC) (since 2002) initially of 40 t carcass mass of Elephant Fish for the Shark Gillnet and Shark Hook Sectors, 15 t for the South East Trawl Sector, and 28 t for other sectors and a component for discards. An overall TAC of 109 t across all sectors applied in 2013–14 (Marton and Curtotti 2014). Input controls include limits on length of net (since 1988), various 4 to 6 week closed seasons to protect pregnant females of School Shark during October to December (1953–67 and 1993–94), and a legal minimum mesh-size of 6 inches for gillnets (since 1975) for most of the fished area. A 3 nautical mile closure of all Victorian waters since 1988 to shark gillnet fishing provides a large refuge for the Elephant Fish (Walker 1999).
Several recent management measures in southern Australia benefit the conservation of Elephant Fish.
In New Zealand, TACs have been in place since 1986 and the catch per unit effort trend increased during 1989 to 2001. As a result, the TAC increased from 619 to 1,040 tonnes over this time period (Annala et al. 2002).
There are recreational bag limits of 20 fish per day in New Zealand and 1 fish per day in Victoria.
|Citation:||Walker, T.I., Francis, M.P. & Reardon, M.B. 2015. Callorhinchus milii. The IUCN Red List of Threatened Species 2015: e.T41743A68610951.Downloaded on 12 December 2017.|