© Baker, J.L. (2009) Marine Species of Conservation Concern in South Australia Full citation Baker, J.L. (2009) Marine Species of Conservation Concern in South Australia: Volume 1 - Bony and Cartilaginous Fishes. Report for the South Australian Working Group for Marine Species of Conservation Concern. J. Baker (consultant); Science and Conservation Division, and Coast and Marine Conservation branches of S.A. Department for Environment and Heritage (DEH); Marine and Coastal Community Network of S.A. (MCCN), and Threatened Species Network (TSN). Web version published by Reef Watch, South Australia.

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Southern Conger Eel & Short-finned Conger Eel / Eastern Conger Eel

Family Name:	Congridae
Scientific Name:	Southern: Conger verreauxi Kaup, 1856 Short-finned / Eastern: C. wilsoni (Bloch & Schneider, 1801)
Recommended Status in S.A:	both possibly Near Threatened (State and Commonwealth)
Rationale:  Although Southern Conger Eel and Short-finned Conger Eel have wide geographic distributions, both species are included here because (i) species in Congridae have life history characteristics which make them vulnerable to over-exploitation and population decline, such as relatively long-life span (more than 15 years), delayed onset of maturity (more than 5 years), low frequency of production (possibly once in a lifetime), and reportedly high mortality of eggs and larvae; (ii) both species apparently have a limited depth range for most parts of the life history, in upper (C. wilsoni) and upper to mid (C. verreauxi) continental shelf waters; (iii) very little is known about the habitat requirements, full depth range, relative abundance, habits, and life history / population dynamics of these species in southern Australia; (iv) both species are reported to have a very low resilience to exploitation; (v) although the nocturnal habits of C. verreauxi and C. wilsoni help to reduce the risk of over-exploitation in some fisheries, both species are fished commercially, and, in many parts of the range, populations of Southern Conger and Short-finned Conger are vulnerable to by-catch mortality in fish trawls (State and Commonwealth), prawn trawls (State), and/or rock lobster pots (State), amongst other gear; (vi) rock lobster pots attract Conger eels (which prey on rock lobsters), and such pots may be one of the most significant sources of mortality in areas where conger eel populations and rock lobster fisheries coincide; (vii) risk assessments in Commonwealth trawl fisheries in southern Australia have listed one or both species as being at medium risk of population impacts from trawl capture; (viii) both species are taken by recreational fishers (anglers, netters and spear fishers), with no catch limits or other management regulations in any State, and there are insufficient data on Conger population sizes and recreational catches to determine the possible population impacts; (ix) generally, strongly site-associated (territorial) benthic species may be vulnerable to site-specific habitat impacts (e.g. from trawling) and (x) degradation of nearshore reefs may be a threatening process in some areas, but there are no specific data.

Page Contents

Current Conservation Status

No listings known

Distribution

Global

The Southern Conger Eel occurs across New Zealand (particularly rocky coasts of the southern North Island, and northern South Island), and in southern and south-eastern Australia (Paxton et al., 1989; Francis, 1996; Edgar, 2000; Heemstra et al., 2004). In New Zealand, the species is widespread, and has been recorded from 12 of 16 marine regions in that country (Francis, 1996).
The Short-finned Conger Eel (Eastern Conger Eel) is found around south-eastern and south-western Australia, Lord Howe I., Norfolk I., New Zealand and Kermadec Is., South Africa, Mozambique, Maldives, Réunion, Mauritius, and Rodriguez (Paxton et al., 1989; Paulin et al., 1989; Francis, 1993; Fricke, 1999; Edgar, 2000; Letourneur et al., 2004; Sink et al., 2004). In New Zealand, it has been recorded mainly in the north, and is considered to be sub-tropical in distribution (Francis, 1996; Brook, 2002). Hawke Bay is generally considered to be the southern limit of C. wilsoni in New Zealand (Roberts and Stewart, 2003). It is noted that there is a verified specimen in the South African Museum from Gough Island (Andrew et al., 1995), which is well south of the sub-tropics.

Southern Australia

In Australia, the Southern Conger Eel occurs in southern New South Wales, Victoria, all sides of Tasmania, Kent Group and other parts of Bass Strait, and south-eastern South Australia, with the upper South-East of S.A. and Kangaroo Island being the western limit (Edgar, 1984; Hutchins and Swainston, 1986; Paxton et al., 1989; Castle, in Gomon et al., 1994; Edgar, 2000; B. Hutchins, W.A. Museum, pers. comm., 2006).
The Short-finned Conger Eel (Eastern Conger Eel) has a disjunct distribution within Australia. On the eastern Australian coast, it ranges from southern Queensland to southern New South Wales (also Lord Howe Island), and on the southern coast, it ranges from eastern South Australia (e.g. Kangaroo Island) to south-western W.A. (Marges, 1998; Edgar, 2000; Australian Museum, 2003y, 2003z; Hutchins, 2005).
The Short-finned Conger Eel tends to occur in that part of south-eastern Australia in which the Southern Conger Eel is absent (Edgar, 2000).
During a survey of fish habitats in south-western Australia, C. wilsoni was recorded only at night, not during the day (Harvey et al., 2004).  

South Australia

In South Australia, conger eels are uncommonly recorded off most parts of the coast, including the central Great Australian Bight (GAB); eastern GAB (e.g. Anxious Bay and other areas off the western side of Eyre Peninsula); lower western Eyre Peninsula (e.g. waters both north and south of the Coffin Bay Peninsula); Kangaroo Island (e.g. eastern, western and southern sides); southern Spencer Gulf (e.g. Hardwicke Bay); islands south of southern Spencer Gulf; Investigator Strait; Encounter Bay (including islands), and the South East (to the Victorian border) (Glover, 1979; Johnson, 1985b; Australian Anglers Association record, 1990; S.A. commercial fishing data, 1995-1997; MLSSA, 1999; Edgar, 2000; Museum of Victoria record, cited in OZCAM database, 2007).
There are several CSIRO Marine Research survey records (unverified) of C. verreauxi from the deeper shelf waters of the central and western Great Australian Bight of S.A., towards the W.A. / S.A. border (CSIRO Marine Research survey data, 1965, 1966, cited in CSIRO, 2007).
The low number of records in the shallow (non-trawled) part of the range may be due to lack of targeted searches at night, when Conger Eels are active.

Habitat

The Southern Conger Eel inhabits sheltered and moderately exposed reef, from near the surface, down to around 80m depth (Edgar, 2000).
The Short-finned Conger Eel is demersal on sheltered rocky reef, and is also commonly found near the mouths of sheltered estuaries, amongst seagrass debris, and near jetty piles and artificial reefs / wrecks (May and Maxwell, 1986; Hutchins and Thompson, 1983; Hutchins and Swainston, 1986; Edgar, 2000; B. Hutchins, W.A. Museum, pers. comm., 2006).
During a survey in south-western Australia, C. wilsoni was recorded occasionally on reefs and under jetties in mainland bays, and on reefs around islands in the Recherche Archipelago (Hutchins, 2005).
The depth range for C. wilsoni is reported to be from near the surface down to about 10m (Edgar, 2000) or to 30m (Castle, 1986, cited in Froese and Pauly, 2007).

Notes on the Biology

Size and Age

C. verreauxi grows to about 2m long, and C. wilsoni grows to about 1.6m long (Castle, in Gomon et al., 1994; Hutchins and Swainston, 2001; Australian Museum, 2003y, 2003z). In New Zealand, there are size records of 2.2m for C. verreauxi.
The maximum weights of captured Southern Conger Eel and Short-finned Conger Eel in southern Australia are 19.05kg and 11.25kg respectively (Hutchins and Swainston, 2001; Australian Underwater Federation, 2003).
There appears to be no existing information on maximum age in these two species; however a related species from Europe (e.g. Conger conger) has been aged to 19 years (Flores-Hernandez, 1990, cited in Froese and Pauly, 2006), and it could be assumed that similarly large species of conger are also relatively long-lived.

Diet and Feeding Behaviour

Conger Eels feed on small fishes (including flathead), crustaceans (especially crabs, but also rock lobsters, including Jasus edwardsii) and cephalopods (including squid and octopus), primarily at night, using their strong sense of smell (Thompson, 1891, and Graham, 1939, cited by Russell, 1983; Winstanley, 1977; Howard, 1988; Nelson, 1994; Australian Museum, 2003y).
Conger species are active at night when they swim over reefs in search of food (Hutchins and Swainston, 1986; Harvey et al., 2004).

Reproduction

Although there appears to be no specific information on reproduction in these two species, members of the sub-family Congrinae (to which C. verreauxi and C. wilsoni belong), are known to reproduce only once in life, after a delayed period to maturity (5-15 years), and females are usually 10 or more years old at age of maturity (Maigret and Ly, 1986; Bauchot and Saldanha, 1986; Göthel, 1992, cited in Froese and Pauly, 2007).
The distinctive larvae of Conger species are abundant in the open ocean (Castle, in Gomon et al., 1994). Castle (1986, cited by Andrew et al., 1995) estimated the larval life of Conger species to be about 1 year, which would facilitate long-range dispersal.

Other Notes on the Biology

Both C. verreauxi and C. wilsoni remain hidden in caves or crevices during the day, and move about at night, to feed (Hutchins and Swainston, 1986; Edgar, 2000; Harvey et al., 2004).

Fisheries Information

Southern Australia – Commercial

The flesh of C. wilsoni is described as being “highly esteemed” (Castle, 1986, cited in Froese and Pauly, 2007).
Conger Eels were regarded as an important market fish during the 19^th century in Australia, but less so during the 20^th century (BRR, 1991). During that time, catch statistics were combined with those for Anguilla eels (fresh water). During the 1970s, the reported catch for southern Australia of Anguilla and Conger eels combined, ranged between 10t and 80t per annum, with the majority of this catch coming from New South Wales (BRR, 1991). During the 1980s, catches ranged between 30t and 120t per annum, again mostly from N.S.W., with a minor component (~10%) from South Australia). The proportion of the catch that is Conger compared with Anguilla cannot be determined from available data (BRR, 1991). C. verreauxi and C. wilsoni are still a commercial species, and “Conger Eel” is the marketing name for both species (Seafood Services Australia, 2003). According to Bureau of Rural Sciences (2006), most catches of C. wilsoni and C. verreauxi come from coastal N.S.W., with minor localised catch of C. verreauxi from Victoria.
Both C. wilsoni and C. verreauxi are taken as bycatch in the Commonwealth-managed SESSF (Southern and Eastern Scalefish and Shark Fisheries) (AFMA, 2002a). C. verreauxi is listed as a bycatch species in (i) the South East Trawl Fishery (SETF), (ii) the Gillnet, Hook and Trap Fishery, and (iii) the Great Australian Bight Trawl Fishery (Bromhead and Bolton, 2005). C. wilsoni is listed as a discarded bycatch species in the SETF, and the Coral Sea fishery (Bromhead and Bolton, 2006). In southern Australia, both C. verreauxi and C. wilsoni are listed as retained bycatch species in the South East Trawl Fishery, for which records are kept in daily logbooks (Wayte, et al., 2004). In the otter trawl sub-fishery of the South East Trawl Fishery, an Integrated Scientific Monitoring Program (ISMP reported that in 14 trawl shots, 60kg of C. verreauxi were retained and 17kg were discarded, and approximately 1 kg of C. wilsoni was discarded in 1 trawl shot (Wayte et al., 2004). These figures may underestimate the total catch. In that fishery, the ISMP also reported that in 109 trawl shots, an additional 136kg of eels in Congridae were retained and 298kg were discarded (Wayte et al., 2004).
In the Gillnet, Hook and Trap fishery (GHT), C. verreauxi is a bycatch of the scalefish demersal long-line sub-fishery, the scalefish automatic long-line sub-fishery, and the scalefish dropline sub-fishery (Webb et al., 2004). Between July 2002 and June 2003, an Integrated Scientific Monitoring Program (ISMP) for the fishery recorded Southern Conger in 25 shots, with 1kg retained and 62kg discarded (Webb et al., 2004). Conger Eels are also part of the bycatch in the scalefish trap sub-fishery of the GHT (Web et al., 2004).
There are records of C. verreauxi being taken by commercial fishing in Port Phillip Bay and Bass Strait in Victoria (Anonymous, 2002b).
In Tasmania, C. verreauxi is a bycatch species in the inshore gillnet fishery for reef fish (Murphy and Lyle, 1999).
In N.S.W., both Conger Eel and Short-finned Conger Eel are commercial species with market prices (N.S.W. Fisheries, undated). The N.S.W. Marine Parks Authority (2001) reported that during 1996/97 and 1997/98, the quantity of Conger Eels (unspecified species) taken by fisheries in N.S.W., were 13.8t and 7.8t respectively, plus an additional 955kg of C. wilsoni was taken in 1996/97. In N.S.W., C. wilsoni and /or C. verreauxi are retained bycatch in the Ocean Trap and Line Fishery (as is Southern Conger) (N.S.W. DPI, 2005), the Estuary General Fishery (New South Wales Fisheries, 2001), in which C. verreauxi is listed as a “secondary species”, and the Estuary Prawn Trawl fishery, where it is a bycatch of prawn fishing and squid fishing (New South Wales Fisheries, 2002). There are records of C. verreauxi being taken by hook and line in deeper waters of the continental shelf in N.S.W. (e.g. Australian Museum, 2003y).
In southern Australia, C. wilsoni is taken as bycatch in rock lobster pots (Edgar, 2000). For example, during a bycatch study in which contents of 3,115 pot lifts were examined in October 2004, a total of 87 individuals of C. verrauxi was recorded (Revill, 2006). In another study of bycatch in the Tasmanian Rock Lobster fishery, 18,302 rock lobster pots (without escape gaps) were examined between 1992 and 1997. During that period, 865 C. verreauxi were caught (i.e. an estimate of 21 pot-lifts required for the capture of 1 animal) (Frusher and Gibson, 1998, cited by Ford, 2001). The study also showed that steel lobster pots with escape gaps can significantly reduce the number of conger eels caught, by more than 80% (Frusher and Gibson, 1998, cited by Ford, 2001).
C. verreauxi is collected in Tasmania for the aquarium industry. The permitted annual catch limit is 60 individuals, with a fishing block limit (6 x 6 nautical miles) of 10 individuals (DPIWE Tasmania, 2005b; Australian Government DEH, 2005b).

Southern Australia – Recreational

Southern Conger Eel are sometimes taken by line fishers (Edgar, 2000), and some fishing clubs and associations keep records of the maximum sizes caught (e.g. Australian Anglers Association Victorian division and W.A. division). The Victorian angling record is a 12.4kg specimen, taken from Western Port Bay in 1982 (AAA – Victorian Division, 2003). There are fishing web sites (e.g. in Victoria) on which are posted photographs of very large adult conger eels taken by recreational fishers.
In Tasmania, Southern Conger Eel is taken by angling (Lyle and Campbell, 1999) and by recreational gillnetting (e.g. on reefs in SE Tasmania - Lyle et al., 2000).
Southern Conger Eel are also taken by spear fishers (Edgar, 2000). The record size of C. verreauxi in Australia (19.05kg) was taken by a spear fisher at Portarlington in Victoria (Australian Underwater Federation, Inc., 2003).
The National Recreational and Indigenous Fishing Survey (Henry and Lyle, 2003) recorded a total of 474 Conger Eels (species unspecified) being caught and kept in southern Australian States during the survey period of May 2000 to April 2001, including 145 from Tasmania, and 260 from Western Australia.

South Australia – Commercial

Conger Eels (species unspecified) are taken as bycatch in the South Australian Marine Scalefish Fishery. Recent catch data are not available for this report, however during the mid-late 1990s, catches in the order of 1.5t – 5t per annum were taken in each of the 1 degree fishing blocks of the lower South East (between Cape Jaffa and the Victorian border). Catches over 1t per annum have also been taken in the Anxious Bay area.  During that period, minor catches (less than 500g per annum) were also recorded in other coastal areas, such as southern Eyre Peninsula, southern and western Kangaroo Island, deeper waters south of Spencer Gulf, and Investigator Strait.
Conger Eels are permitted by-product in the South Australian Rock Lobster Fishery (Sloan, 2003a). Prescott and Xiao (2001) reported that 72 conger eel specimens were caught in 76 lobster pots, during sampling of 32,000 pots in the Northern Zone Rock Lobster fishery in S.A., in 1991 – 1992. For the Southern Zone (21,000 pots sampled), 26 conger eels were recorded in 27 lobster pots during the 1991-92 season (Prescott and Xiao, 2001). During a more recent bycatch monitoring program in this fishery, several hundred Conger Eel specimens were recorded from both the Northern Zone and Southern Zone, in 2001/02 and 2002/03. Catches are shown in the table below (from Brock et al., 2004). By-catch from half of the total number of pot lifts per annum was recorded and therefore, the total catch (from all pots) per annum could be in the vicinity of 500 to 600 specimens in the Northern Zone, and about 800 specimens in the Southern Zone. During this program, the bycatch was also sampled from 1% of the total number of pot lifts during the 2002/03 fishing season, and 8 specimens of C. verreauxi were recorded in the Northern Zone, and 27 in the Southern Zone. Based on bycatch sampling by observers, the annual catches of Conger Eel in the Northern Zone and Southern Zone may in the vicinity of 800 specimens in the Northern Zone, and 2,700 in the Southern Zone, the latter of which is more than three times the catch estimated from logbook data. Regardless of the differences in results according to sampling methods, the rock lobster bycatch survey program data indicate that hundreds of specimens per annum are taken as bycatch in this fishery (Table 3).

Table 3 Proportional Catch of Conger Eel in the S.A. Rock Lobster Fishery.
Northern Zone	No. pot lifts (and percentage of total)	No. C. verreauxi specimens caught
2001/02	320,003 (51%)	247
2002/03	265,843 (47%)	283
Southern Zone
2001/02	545,886 (60%)	422
2002/03	486,155 (57%)	453
from Log Book Monitoring 2001-2003 (Brock et al., 2004)

South Australia – Recreational

Conger Eels are occasionally taken by anglers in South Australia. It is noted that one of the Australian fishing record specimens (12.5kg specimen) of C. verreauxi, was taken in 1990 from Granite I. in S.A. (Australian Anglers Association, 2003).
Of the 474 Conger Eels (species unspecified) recorded by the National Recreational and Indigenous Fishing Survey (Henry and Lyle, 2003) as being caught and kept by recreational fishers in southern Australian States during the survey period of May 2000 to April 2001, 69 of those specimens were taken in South Australia.
During the 1980’s Conger eels over 1kg were eligible species for “weighing in” during national spearfishing competitions, including those held in South Australia (Johnson, 1985a, 1985b).  More recently, Conger Eel (specimens over 1kg) was listed as one of the targets in the 54th Australian Spearfishing Titles 2006, held on northern Kangaroo Island (Australian Underwater Federation Inc., 2006).

New Zealand

In New Zealand, both conger eels are a small commercial resource. They are caught incidentally all year round by long-liners and trawlers, and also as a bycatch of the rock lobster fishery (Armitage et al., 1994). For Southern Conger Eel, the average length and weight of commercial specimens in New Zealand are 100-150cm and 3-5kg respectively.
A gill net fishing experiment in New Zealand (Hickford et al., 1997) has shown that C. verreauxi is likely to be minor part of the bycatch in the commercial gillnet fishery.
Conger verreauxi is one of the fish species that has traditionally been taken by Maori fishers (Barber, 2003).
The conger eel fishery in New Zealand is small (i.e. 100- 200 tonnes per annum during the past 10 years to 2005). Catch is mainly made up of the three species (Conger verreauxi, C. wilsoni, C. cinereus). Other species are rarely caught. Most conger eels caught commercially are landed headed and gutted for further processing, although a small quantity is sold alive. Congers are caught as bycatch of trawling (red cod and flatfish), lining (snapper and hapuku) and potting (rock lobster and blue cod). The N.Z. Ministry of Fisheries (2005) considered it likely that there is a considerable unreported bycatch of conger eels that is discarded, particularly so in the early 1990s.
There is a proposal to add stocks of both conger eel species (C. verreauxi and C. wilsoni) to the quota management system (New Zealand Ministry of Fisheries, 2005).

Vulnerable Characteristics of the Species

Although there is no specific information on the reproduction of C. verreauxi and C. wilsoni, closely related members of the genus are known to be relatively long-lived, with delayed age at maturity (e.g. up to 10 or more years for females), reproducing only once in life. As is the case for other congers, Conger wilsoni and C. verreauxi respectively are reported to have very low resilience to exploitation, in terms of minimum population doubling time (based on growth and/or fecundity parameters) (Froese and Pauly, 2006). Low productivity of conger eels results from their longevity (average lifespan between 5 and 15 years), low frequency of breeding, and high mortality of eggs and larvae (New Zealand Ministry of Fisheries, 2005).

Threatening Processes

Conger eels are likely to be susceptible to over-fishing and local depletion because they are localised fish on coastal reefs and in other nearshore environments, very territorial, and are known to have low productivity (N.Z. Ministry of Fisheries, 2005). There are no specific data for S.A. on the potential impacts of fishing; however, it is noted that an eastern Australian study of the susceptibility of trawl-caught fishes to population impacts (Stobutski et al., 2001) included Conger eels. The study ranked fish bycatch species according to: (i) the susceptibility to capture and mortality due to prawn trawling, and (ii) the population's capacity to recover after depletion. The rank of each species determined its relative capacity to sustain trawling, and therefore its priority for research and management. Species that were the least likely to be sustainable included those in the Congridae. These species are highly susceptible to capture by trawls, they are benthic or demersal, and their diet may include animals targeted in commercial fisheries. The recovery capacity of such species is also low, with the estimated removal rate by trawling (Stobutski et al., 2001). In a draft risk assessment for species in the SETF (Wayte et al. 2004), 3 “productivity attributes” and 6 “susceptibility attributes” were used to classify C. wilsoni as being at “medium risk” of potential population impacts from trawling in that fishery. In a similar assessment for the GABTF, C. verreauxi was listed as being at “medium risk” of population impacts from bycatch in that fishery (Daley et al., 2006). C. verreauxi is listed as being at “low risk” of population impacts in the scalefish demersal long-line, scalefish automatic long-line and scalefish drop line sub-fisheries of the GHT Fishery (Webb et al., 2004), presumably due to low catch numbers.
Rock lobster pots attract Conger eels (which prey on rock lobsters), and such pots may be one of the most significant sources of mortality in areas where conger eel populations and rock lobster fisheries coincide.
Conger eels are found in nearshore reef habitats, and in some parts of the range, such habitats are degraded, particularly metropolitan areas (e.g. see Cheshire and Westphalen, 2002 and Turner et al., 2007, for examples from the metropolitan coast of Gulf St Vincent in South Australia).

Research Requirements

Generally, the life history, habitats, habits and ecological needs of Conger eels are poorly known and under-researched in southern Australia.
Where possible, surveys should be undertaken to determine the distribution and relative abundance of Conger eels in nearshore areas, including parts of South Australia. Conger eels are rarely recorded in fish surveys, due to lack of targeted sampling for nocturnally active species.

Management Requirements

Species-specific quantification of Conger eel catches in commercial and recreational fisheries is required across southern Australia, including South Australia.
Stock assessments are required for commercial fisheries of Conger Eels, including those where the species are part of the by-product.
Methods to reduce the bycatch of conger eels in rock lobster pots should be adopted (e.g. escape gaps should be a requirement in all rock lobster fisheries).
Where possible, measures should be adopted to reduce the bycatch of conger eels in Commonwealth-managed trawl fisheries.
Nearshore reef protection programs in southern Australian States should consider the life history, habitats, habits and ecological needs of Conger eels (see also Research Requirements, above).

Other Information

C. verreauxi occurs in a number of marine parks in Victoria, including Wilsons Promontory (Edmunds et al., 2003). It is also found in various marine protected areas in New Zealand, such as Goat Island (Anthoni, 1997); Long Island-Kokomohua Marine Reserve in Queen Charlotte Sound (Davidson, 2004), and other protected areas, such as Pauatahanui Wildlife Management Reserve (Whiter, 2005).
C. wilsoni is targeted by some fisheries in South Africa (Sink et al., 2004).