© 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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River Garfish

Family Name:	Hemiramphidae / Hemirhamphidae
Scientific Name:	Hyporhamphus regularis ardelio Whitley, 1931) (Eastern form); H. regularis regularis (Günther, 1866) (Western form)
Recommended Status:	South Australia: Data Deficient
Rationale:  Both forms of River Garfish are included here because (i) South Australia is at the edge of a discontinuous range in southern Australia, and there are few permanent estuarine areas in S.A. that could support populations of either form of this species; (ii) River Garfish is a site-associated, shallow water species; it may depend upon estuarine habitats (particularly estuarine seagrass beds) and coastal lakes throughout the life cycle, and be unable to move away from such environments if the quality and quantity of critical habitat is degraded; (iii) River Garfish may have low fecundity (and therefore likely low reproductive output); (iv) in South Australia, all of the estuarine areas in which the River Garfish is found, are subject to numerous impacts from pollutants, restrictions to (or other alterations to) flow, reduction in water quality, and/or other forms of habitat alteration and degradation. There is no knowledge of population sizes or population dynamics of River Garfish in South Australia, nor quantitative information on fishing, nor species-specific information on the effects of habitat degradation, the latter likely the main threatening process. It is noted that in New South Wales, this species aggregates during the winter to spawn, which increases the vulnerability of the eastern form of River Garfish to fishing mortality. Fishers in New South Wales target the winter spawning aggregations, and in south-eastern Australia, fishing is a threatening process for the species. In N.S.W., where River Garfish is heavily targeted, significant (order of magnitude) declines in landings have been recorded in recent years (compared with the 1970s), but it is not known to what extent this relates to change in fishing practices compared with decline in the population. River Garfish are considered to be fully fished in New South Wales, and might be Near Threatened in status (due to probable over-fishing, coupled with impacts on habitat due to coastal development), but the status in South Australia and Victoria (and possibly W.A.) can be considered Data Deficient.

Page Contents

Current Conservation Status

No formal listings, but it is noted that the Eastern River Garfish is classified as fully fished in New South Wales (N.S.W. DPI, 2007h).

Distribution

The Eastern River Garfish (Hyporhamphus regularis ardelio) mainly occurs in eastern Australia from Gladstone, Queensland, southwards in coastal rivers and estuaries to Lakes Entrance in Victoria (Collette, 1974, 2004; Classon and Booth, 2002); however, the species extends westwards into South Australia, where it has a permanent presence (Glover, 1985). Many estuaries in New South Wales contain Eastern River Garfish (Smith, 2002). Eastern River Garfish is considered to be the same species as the Western River Garfish (H. regularis regularis), which occurs in Western Australia.

Previously, Collette (1974) and Paxton et al. (1989) listed the distribution of Western River Garfish H. regularis regularis as being from Bunbury to Shark Bay in W.A. However, Glover (1984) reported that H. regularis regularis was first recorded in South Australia in 1984, and that the species probably has a permanent presence in South Australia. Similarly, Gomon et al. (1994) reported that H. regularis regularis extends as far east as Gulf St Vincent in S.A. (based on records from Angas Inlet, in the Port River - Barker Inlet system, collected 1984, identified by M. Gomon).

In South Australia, River Garfish has been recorded in the Port River - Barker Inlet system (Glover, 1984; Jones et al. 1996, Noell, 2003; and S.A. Museum records, 1984 and 1995), in variable numbers over a 10 year period (Jackson and Jones, 1999). The species has also been recorded in West Lakes (Cheshire et al., 2002); the Onkaparinga estuary in Gulf St Vincent (Branden, 1974; S.A. Museum record, 2000; Hammer, 2006a); and in the Coorong / Murray Mouth area (e.g. Goolwa, Tauwitchere, Boundary Creek) (Smithsonian Museum record, cited in Anonymous, 2001a; Ye et al., 2002; Higham et al., 2002; PIRSA, 2005a).

The two sub-species are geographically separated, but morphologically similar (Collette, 1974; Smith, 2002), and South Australia is at the edge of the range for this species.

Habitat

The River Garfish (both forms) is typically associated with seagrass (particularly eelgrass beds) in coastal lakes, rivers and estuaries, including brackish waters (Gomon et al., 1994; Jones et al., 1996; Smith, 2002).

The Eastern River Garfish has occasionally been recorded in fresh water (e.g. New South Wales) (N.S.W. DPI, 2007h).

In some areas of South Australia, the River Garfish co-occurs with Southern Sea Garfish, in locations such as the Coorong (Collette, 1974); Port River - Barker Inlet Estuary (Noell, 2003; Jones et al., 1996) and the Onkaparinga River (C. Noell, pers. obs., cited by Noell and Ye, 2008).

In south-western Australia, H. regularis regularis has been recorded in estuaries, such as the Peel-Harvey (e.g. Potter et al., 1983) and Canning River (record by B. Collette, 1970, cited in Anonymous, 2001).

Notes on Biology and Behaviour

Age and Growth

River Garfish grows to around 35 - 37cm including beak (Collette, 1974; Gomon et al., 1994; Hutchins and Swainston, 1986; 2001; Smith, 2002); however less than 32cm is a common size observed. It is noted that in surveys undertaken during the early 2000s in the Murray Mouth area, Ye et al. (2002) recorded River Garfish in the narrow size range of 10cm – 12.1cm, in that area.

River Garfish may reach nearly 200g maximum weight, although specimens of around 100g are commonly caught and marketed in the eastern States.

A validated ageing study using otoliths showed that Eastern River Garfish is moderately long-lived, with maximum observed ages of 7+ years old (Stewart and Hughes, 2007).

Females of Eastern River Garfish grow faster and attained greater fork lengths than males (Stewart and Hughes, 2007).

Diet and Feeding Behaviour

The River Garfish consumes large quantities of eel grass (e.g. Zostera spp.), as well as algae, diatoms and insects (Thomson, 1959; Grant, 1987, cited by Smith, 2002).

A carbon isotope study in south-eastern Queensland showed that Eastern River Garfish commence life as carnivores (eating zooplankton such as Temora turbinata) and change to a diet in which seagrass (e.g. Zostera muelleri - formerly Z. capricorni) is the primary carbon source (Carseldine and Tibbetts, 2005). The ontogenetic trophic shift from an animal to plant diet occurs between 80 and 110mm (Tibbetts and Carseldine, 2007). After the ontogenetic shift, the diet is dominated by Zostera muelleri, and feeding occurs mainly during the day, with gut fullness dropping markedly after dusk. However, they always depend on animal matter to some extent, throughout life (Carseldine and Tibbetts, 2005). Due to the low percentage of nitrogen in Z. muelleri (2.5%) compared to zooplankton (9.1%), the authors concluded that nitrogen from zooplankton may be necessary throughout the life history, with the carbon requirements for these fish coming chiefly from Z. muelleri (Carseldine and Tibbetts, 2005).

Migration

River Garfish have been observed up to 200km inland from the sea (Classon and Booth, 2002).

Reproduction

Size at 50% maturity is similar for male and female Eastern River Garfish (Hughes and Stewart, 2006). They mature at about 16cm (N.S.W. DPI, 2007h).

Some north coast fishers in New South Wales have reported development of gonads in River Garfish in October - November. Eastern River Garfish spawn between July and December in N.S.W. estuaries (Hughes and Stewart, 2006).

In a study of Eastern River Garfish in New South Wales estuaries, sex ratios were significantly biased toward females in all estuaries sampled. Mean (plus or minus SE) batch fecundity was 917 plus or minus 36 (range: 102 – 2,268) ripe oocytes per female, and there is a linear relationship between batch fecundity and fish size (Hughes and Stewart, 2006).

Eastern River Garfish spawn early, in the spawning season immediately following the one in which they were born (Hughes and Stewart, 2006).

A study in New South Wales showed that mature female fish of Eastern River Garfish are multiple batch spawners (Hughes and Stewart, 2006).

The fact that River Garfish are landed in estuaries throughout the year suggests that this species may complete its life cycle within estuarine waters (Smith, 2002).

River Garfish attaches its eggs to seagrass (Classon and Booth, 2002).

Fisheries Information

Eastern and Southern Australia

Eastern River Garfish is fished commercially and recreationally in the eastern States.

Eastern River Garfish is taken in the Great Barrier Reef fishery in Queensland, for both bait, and sale to markets as a food fish (Gehrke and Sheaves, 2006).

Eastern River Garfish is one of 3 garfish species fished commercially in New South Wales (Smith, 2002). Almost all of the catch is taken in the winter months, in the Estuary General fishery (N.S.W. DPI, 2007h). In New South Wales, BRR (1991) reported catches of Eastern River Garfish in the order of 55t – 95t per annum during the mid 1960s to mid 1970s; high catches of 115t and 136t in 1974/75 and 1973/74 respectively; and catches ranging from approximately 20t to 60t per annum from the mid 1970s to 1990. Smith (2002) reported that commercial landings of River Garfish in N.S.W. averaged 85.1 t annually between 1952/53 and 1977/78. In contrast, commercial landings since 1977/78 have been low and relatively stable, averaging 36.2 t annually between 1977/78 and 1999/00. The cause of the dramatic decline in total landings of River Garfish in the mid-1970’s is unclear, but is coincident with a dramatic increase in Sea Garfish landings, which suggests better species discrimination by fishers and/or a transfer of fishing effort from River Garfish to Sea Garfish (Smith, 2002). Virtually all commercial landings of Eastern River Garfish in N.S.W. are reported in estuaries. The majority of landings during the 1990s and 2000s occurred within Tuggerah Lakes, Lake Illawarra, Wallis Lake, Clarence River and Port Stephens (Smith, 2002; N.S.W. DPI, 2007h). Small quantities of landings in numerous other estuaries suggest that many N.S.W. estuaries sustain populations of River Garfish. Two thirds of the commercial catch is taken north of Sydney. It is not known whether the distribution of landings reflects the relative abundance of garfish between estuaries (Smith, 2002). The main fishing method for taking River Garfish in N.S.W. is “bull-ringing” (i.e. boat-based mesh nets used in shallow water), which comprises about 70% of the catch. Minor quantities are caught by other methods, such as meshing nets, beach haul, garfish haul, general purpose net and other gear (Smith, 2002). There is a ban on the use of garfish bull-ringing nets in estuaries, during December and January (Smith, 2002).

In N.S.W., River Garfish is one of the bycatch species in the estuarine prawn haul fishery, in estuaries such as the Richmond and Wallamba rivers (Gray and Kennelly, 2001). Surveys have shown that when taken as bycatch in Botany Bay, Lake Macquarie and Clarence River, the species is retained. Between February 1998 and January 1999, it is estimated that 9,708 (SE = 2,248) River Garfish taken in the estuarine prawn haul fishery in Lake Macquarie, were retained, and 1,517 (SE = 890) were discarded (Gray and Kennelly, 2001).

River Garfish are a very minor part of the bycatch in the N.S.W. Ocean Hauling Fishery, in which commercial hauling and purse seine nets operate from sea beaches and in ocean waters within 3 nautical miles of the N.S.W. coast (New South Wales Fisheries, 2004b).

In Victoria, catches of River Garfish from the Gippsland Lakes and Lake Tyers have been more than 20t per annum in some years during the 1980s (e.g. 51t in 1981/82; 31t in 1983/84); however, in most years since the 1970s, annual catches have been less than 10 tonnes (NRE Victoria, 2007). The commercial catch (in tonnes live weight) of River Garfish from Victoria in recent years is shown in the table below (from NRE Victoria, 2002, 2003, 2007).

Commercial Catch of River Garfish in Victorian Waters 1997 – 2007
Year	Catch (t)
1997/98	4
1998/99	14
1999/00	6
2000/01	10
2001/02	3
2002/03	3
2003/04	1
2004/05	8
2005/06	na
2006/07	na
(DNRE Victoria, 2002 - 2007)
na = data not available, due to confidentiality constraint (< 5 fishers)

River Garfish is one of the species caught in the bycatch of the commercial eel fishery in Victoria (DPI Victoria, 2003), however data are not available for this report.

During the past decade, commercial landings of River Garfish have been insignificant in W.A. (e.g. 54kg in 1998/99, and none in recent years). Previously, catches in the order of several tonnes per annum were reported during the 1970s and 1980s (with a high of almost 11t in 1977/78) (BRR, 1991).

As a species for anglers, River Garfish is described as “good eating” (Classon and Booth, 2002).

Eastern River Garfish is taken by recreational fishers in New South Wales and Victoria, and some clubs keep records of maximum sizes caught (e.g. New South Wales Fishing Clubs Association; Australian Anglers Association). The recreational catch in N.S.W. is estimated to be less than 20t per annum (New South Wales Department of Primary Industries, 2007h).

In estuarine areas along the New South Wales coast, River Garfish are taken both commercially and recreationally by indigenous fishers (Schnierer and Faulkner, 2002, cited by N.S.W. DPI, 2004).

South Australia

In the State-wide commercial fishing catch and effort database system for the Marine Scalefish Fishery in S.A., commercial garfish catches have not traditionally been separated by species for data recording. Thus, the annual proportion of the total “garfish” catch that comprises River Garfish is not known for this report. However, it is noted that River Garfish is specified as a permitted species to be taken in the Lakes and Coorong Fishery, under the Fisheries (Scheme of Management – Lakes and Coorong Fishery) Regulations 1991 (PIRSA, 2005a).

Jones et al. (1996, Table 2) reported that the species is taken by recreational fishers, in areas such as the Port River – Barker Inlet estuary.

No quantitative information on the recreational fishery in South Australia is available. The recent National Recreational and Indigenous Fishing Survey (Henry and Lyle, 2003) did not record garfish by species, hence the proportion of the total garfish catch for each State that is River Garfish, rather than Sea Garfish, cannot be determined with available data.

Vulnerable Characteristics of the Species

River Garfish is a site-associated, shallow-water species. It may be dependent on estuarine habitats (particularly estuarine seagrass beds) and coastal lakes throughout the life cycle, and is unable to move away from such environments if the quality and quantity of critical habitat is degraded.

River Garfish have relatively low fecundity (see Reproduction), and therefore are likely to have low reproductive output.

In New South Wales, this species aggregates during the winter to spawn (Stewart, 2003), which increases the vulnerability of Eastern River Garfish to fishing mortality. Fishers target the winter spawning aggregations.

Threatening Processes

In South Australia, all of the estuarine areas in which the River Garfish is found, are subject to numerous impacts from pollutants, restrictions to (or other alterations to) flow, reduction in water quality, and/or other forms of habitat alteration and degradation. For example, see Baker (2004) and EPA (2007) on Port River – Barker Inlet estuary; Edyvane et al. (1996), MDBC and Department of Water, Land and Biodiversity SA (2002) and CSIRO (2009), on Coorong and Murray Mouth area, and EPA (2007) on the Onkaparinga estuary. Higham et al. (2002; also cited by PIRSA, 2005a) reported that closure of the Murray Mouth would directly affect this species, by interrupting its life cycle. Closure of the Murray Mouth happens periodically, due to the many impediments that restrict natural seaward flow of fresh water, and exacerbate the build-up of sand at the Mouth. Fresh water flow through the Murray Mouth has been severely restricted during the past decade, and fresh water inflows have reached record low levels.

In south-eastern Australia, fishing is a threatening process for the species. For example, in New South Wales, where River Garfish is heavily targeted, N.S.W. Fisheries reported that there are major concerns over the status of the two major garfish species in N.S.W. (one of which is River Garfish), with the commercial fisheries for Sea Garfish and River Garfish showing large declines in reported landings in recent years. Reported landings of River Garfish from N.S.W. estuaries peaked at more than 100t in 1974/75, but have steadily declined to average less than 30t per year during the last decade (New South Wales Fisheries, 2003d), as discussed in the section above on Fisheries Information. Although some of this decline has been attributed to declining effort (N.S.W. DPI, 2007h), there is concern that fishing mortality and natural mortality are both high, and the stock is classified as fully fished (N.S.W. DPI, 2007h).

In south-eastern Australia, although long term fishing pressure is one possible cause of the decline of River Garfish, another major concern is the impact of coastal development on the habitat of this species, which appears to have a strong reliance upon seagrasses (New South Wales Fisheries, 2003d).

Research Notes

Little is currently known of the biology or habitat requirements of River Garfish; however work has been undertaken by N.S.W. Fisheries and University of Wollongong (Stewart et al., 2005), to investigate the biology and life-history of River Garfish, such as reproductive biology (including time of spawning, and age and size at maturity); the age and size composition and reproductive state of River Garfish in the landed commercial catch; estimates of growth rate; and key habitat requirements, particularly the role of seagrasses and other vegetated areas as juvenile nursery areas, and as sites for feeding, spawning and egg attachment, for adult garfish (New South Wales Fisheries, 2003d). The project has provided the research basis for a stock assessment of River Garfish (and Eastern Sea Garfish) in N.S.W. waters, including initial assessment of environmental impacts of the fishery, and possible impacts on the fishery.

Management Notes

The project undertaken by N.S.W. Fisheries and the University Wollongong (see above), has provided advice to the fishing industry, fishers, and N.S.W. Fisheries on the management of the River Garfish fishery, including the importance of key habitats for garfish reproduction and feeding, and recommendations for research and monitoring, to assist in achieving a sustainable fishery in New South Wales waters (New South Wales Fisheries, 2003d; Stewart et al., 2005; N.S.W. DPI, 2007h).

Management Recommendations

Catch rates are not a suitable indicator of stock status for aggregating species such as garfishes (N.S.W. DPI, 2007h), hence cautious management is required, regarding allowable catches.

A legal minimum length should be implemented in all commercial and recreational fisheries for River Garfish (both eastern and western forms).