© 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 Sea Garfish / Sea Garfish

Family Name:	Hemiramphidae / Hemirhamphidae
Scientific Name:	Hyporhamphus melanochir (Valenciennes, 1847)
Recommended Status:	South Australia: Near Threatened Other States: Data Deficient
Rationale:  Although Southern Sea Garfish is a widely distributed and abundant species throughout southern Australia, it is included here because (i) it is schooling species, particularly over shallow seagrass beds, and is therefore readily captured by netting and line fishing methods; (ii) as a schooling species, it is easily caught; depletion of schools can commonly occur with catch rates remaining high; therefore, catch rates are considered to be neither a reliable nor sensitive indicator of abundance trends, and population depletion can go unnoticed for a long period; (iii) this is a “delicate” fish, with low prospects of survival when hooked or netted, handled and released; (iv) stock assessment modelling has indicated that recruitment is highly variable over space and time, and may be low for a succession of years, which increases the vulnerability of stocks at local scales to over-exploitation and depletion; (v) there are few fishable age classes of Southern Sea Garfish, and the species is heavily fished both commercially and recreationally across the range, from the time of first recruitment; (vi) the distribution and life history of this species is closely associated with intertidal and shallow subtidal seagrass beds; in addition to fishing pressure, the impact of effluent discharges, dredging and coastal development on the seagrass habitat of this species is considered to be significant threat in a number of States, and (vii) sea level rise due to climate change may impact coastal seagrass habitats that are important as breeding or nursery areas, and this may adversely affect populations over time. This species is most heavily fished in South Australia. In other southern Australian States, full stock assessment is required, and its status will not be assessed here, other than to indicate that this species is highly vulnerable to over-exploitation, and measures to control effort in some States may be inadequate. In South Australia, where Southern Sea Garfish has sustained a commercial fishery for at least 60 years, and a significant research effort has been undertaken during the past decade, this species is now classified as over-fished. In S.A., commercial fishers take the bulk of the catch, but recreational fishers reportedly took about 20% of the total catch in 2000/01. Issues in S.A. include significant biomass reduction and “truncation” of the population age structure; low estimated levels of population egg production; a succession of low recruitment levels; high levels of exploitation (estimated to be 50 – 60% or more of the fishable biomass each year); recruitment over-fishing, and reliance of the commercial fishery on one to two year classes. The exploitation rates in South Australia are reported to be approximately twice the generally accepted safe upper limits for sustainable harvest. During the past decade, recruitment levels have mainly been low. The fishing-induced truncation of age structure increases the vulnerability of the stock to decline, if the fishery is reliant on the strength of a single year class (or two year classes) to persist, particularly if recruitment strength is variable from year to year due to environmental causes. Also, heavy fishing of a single, young year class is not a conservative fishing strategy, because spawning stock biomass has been fished down over time, and little remains to perpetuate the population, or the fishery. It has also been reported that Southern Sea Garfish now mature at a smaller size than was observed 40 years ago, believed to be an evolutionary response to heavy fishing pressure.

Page Contents

Current Conservation Status

No formal listings, but it is noted that in South Australia, at current exploitation rates, Southern Sea Garfish is considered over-fished (Noell et al., 2006; Steer et al., 2009). This species is also considered to be growth over-fished in New South Wales.

Distribution

Southern Australia

Southern Sea Garfish ranges from approximately Eden in New South Wales through to Shark Bay in Western Australia, including Tasmania (Collette, 1974; Gomon et al., 1994).

A stock discrimination study indicated low levels of differentiation among samples taken from across southern Australia; however, sufficient differentiation was found among 4 separate populations of garfish for them to be considered separate management units. These population are based off Western Australia; western South Australia; eastern South Australia (including the gulfs) plus Victoria; and Tasmania, respectively (Donnellan et al., 2002, cited by C. Noell, pers. comm., 2009). The study did not discriminate between fish sampled from the east coast of Tasmania compared with samples from Flinders Island (Donnellan et al. 2002, cited by Lyle and Hodgson, 2002). The four main populations may be further discriminated at a finer spatial scale through analysis of otolith chemistry and morphology (C. Noell, pers. comm., 2009; Steer et al., 2009).

South Australia

In South Australia, Sea Garfish occurs throughout State waters, from the S.A. / W.A. border through to the S.A. / Victorian border. Examples include estuaries and marine waters throughout Gulf St Vincent; all parts of Spencer Gulf; southern Eyre Peninsula; and eastern Great Australian Bight (Branden et al., 1974; Hammer, 2006a; Australian Museum records; S.A. Museum records, CSIRO Marine Research records, in Australian National Fish Collection, cited in OZCAM database, 2009).

Examples of estuaries in which the species has been recorded include many of those in Gulf St Vincent (Salt Creek / Coobowie, Wills Creek, Port River - Barker Inlet, West Lakes, Onkaparinga), and Spencer Gulf (Blanche Harbour, Port Augusta, Port Pirie creeks [including First, Second, Third Creeks], and Fisherman Creek) (Department for Environment and Heritage, South Australia, 2007).

There are records from the Murray Mouth / Goolwa area (e.g. Ye et al., 2002).

Previously, it was reported that the population of Southern Sea Garfish in the west coast region of South Australia may be genetically dissimilar to that which occurs in both gulfs (Donnellan et al., 2002, cited by Jones and Noell, 2005). More recent work, using otolith chemistry, has indicated that the population structuring of Southern Sea Garfish is more complex than previously assumed, and stocks can be discriminated at a much finer spatial scale. For example, garfish collected from sites separated by less than 60 km displayed significantly different chemical signatures of elements in their otoliths, especially during their second year of growth, indicating that they had inhabited different water bodies during their life (Steer et al., 2009). From a broader perspective, Southern Sea Garfish in South Australia can be partitioned into six regional components with various levels of inter-mixing (Steer et al., 2009). In contrast to the aforementioned results, another study in South Australia indicated that length/weight and length/age relationships in garfish do not differ between areas separated by hundreds of kilometres, suggesting large-scale movement (Fowler et al., 2008).

Habitat

Southern Sea Garfish is found inshore, in sheltered coastal waters, such as estuaries, bays, inlets, and gulfs. In such areas, it is mainly associated with seagrass beds and sand habitats. This species also occurs over patches of seagrass near reef. The distribution and life history are closely associated with seagrasses (McArthur et al., 2003; Noell, 2004, cited by Jones and Noell, 2005). Adults mainly occur in seagrass beds (e.g. species of Zostera, Heterozostera and Posidonia), and also macroalgae (Jones et al., 1990; Noell, 2004).

In south-western Australia, H. melanochir may spend the first year of life in estuarine areas, and the first 2 years in inshore waters (Lenanton, 1982).

In South Australia, early juveniles are found in nursery areas such as sheltered bays, tidal creeks, estuaries and shallow seagrass beds, particularly in Gulf St Vincent and Spencer Gulf (Jones et al., 1990). Similarly in eastern Tasmania, small juveniles (0+ cohort) have been caught in shallow sheltered waters (Jordan et al., 1998).

The species has also been recorded over reefs (e.g. at Recherche Archipelago, in south-western W.A.) (Hutchins, 2005) and in the vicinity of other hard structures, such as breakwaters, rock walls and groynes.

In some areas, this species has been recorded in mangroves (e.g. Jones, 1984; Hindell and Jenkins, 2004).

Main depth range is about 0m – 20m (May and Maxwell, 1986), but in the South Australia gulfs, H. melanochir may be found in deeper water during the winter months (Jones et al., 1990, cited in Froese and Pauly, 2009).

In Victoria, Southern Sea Garfish is commonly found in rivers, estuaries and coastal lakes, where it is usually associated with dense bodies of eelgrass (Zostera / Heterozostera seagrass) (Barnham and Raadik, 2007).

Notes on Biology and Behaviour

Age and Growth

Southern Sea Garfish grows to around 50cm (Caton, 2000), but fish of this size are rarely observed. During the 1980s, a study in Baird Bay, South Australia, recorded a significant proportion of garfish over 35cm (up to 41cm) (Jones, 1990).

Work in Tasmania has indicated that H. melanochir grow to about 7cm after one year; about 17 – 20cm by age 2, and about 25-30cm by age 3 (Jordan et al., 1998; Lyle and Hodgson, 2002). This differs from results in other States. Jones et al. (2002) reported that in South Australia, Victoria and Western Australia, Southern Sea Garfish reach 20 – 23cm in about 13 - 15 months. Growth of male and female H. melanochir is relatively rapid for approximately the first 3 years, slowing appreciably when the fish reach about 25cm (approximately age 3). At the maximum age of around 9-10 years, garfish may be 40cm long and weigh around 0.35 kg. In a Tasmania study, after 3-4 years there was an increasing variation in size-at-age, with fish at a length of 30cm ranging from 3 to 8 years old (Jordan et al., 1998). Insufficient data are available to determine whether males and females grow at different rates (Lyle and Hodgson, 2002).

Recent research on Sea Garfish in South Australia has shown that females dominate the sex ratios in the commercial catch; they are also the largest individuals, and the largest from each age class (Fowler et al., 2008). In South Australia, a study indicated that length/weight and length/age relationships do not differ between areas separated by hundreds of kilometres (Fowler et al., 2008).

According to Barnham and Raadik (2007), Southern Sea Garfish grows to 600g, but few fishes of this size have ever been recorded. One of the maximum weights recorded was a specimen of 0.445kg, taken at Coobowie in South Australia, in 2001 (Australian Anglers Association, 2009).

During a study in Tasmania, the oldest fish (female) was aged 8 (Jordan et al., 1998). On the west coast of South Australia, garfish have been aged to 10 years (Jones, 1990), but in more heavily fished gulf waters, this species rarely reaches 8 years (Jones et al., 1990), and garfish usually die much younger. Garfish have also been aged to 10 years in Western Australia (Jones et al., 2002).

Diet and Feeding Behaviour

Southern Sea Garfish are predominantly herbivorous (Klumpp and Nichols, 1983a,b; Edgar and Shaw, 1995b). One study showed that the majority of the diet comprises of seagrass and algal filaments (Klumpp and Nichols, 1983a,b). Other diet items include diatoms, insect larvae, polychaete worms, shrimp larvae, and small crustaceans, particularly amphipods (Thompson, 1957; Robertson and Klumpp, 1983; St Hill 1996, cited by Jordan et al., 1998).

One study showed that Garfish in the size range 10cm to 30cm eat “eelgrass” (e.g. Zostera species, and Heterozostera nigricaulis, previously known as H. tasmanica) during the day, and nocturnally emergent crustaceans (such as amphipods) at night (Robertson and Klumpp, 1983; Klumpp and Nichols, 1983a). Both floating seagrass and live, attached seagrass may be eaten during the day, and the predation of Garfish on amphipods at night is facilitated by vertical migration of the prey up the water column at night (Robertson and Klumpp, 1983).

With increasing size of Garfish, the dependency upon seagrasses in their diet increases (Noell, 2004, cited by Jones and Noell, 2005).

Reproduction

Previous estimates of size and age at maturity are about 23-25cm and at least 2-3 years respectively (Ling, 1958; Kailola et al., 1993; Caton, 2000). In south-eastern Australia, some females mature at 22cm, although most are 25cm in length and up to 4 years old before spawning commences (Barnham and Raadik, 2007).

Ling (1958) and Ye et al. (2002) reported that the Sea Garfish has low fecundity (e.g. in the thousands), producing few, relatively large eggs.

Southern Sea Garfish has a prolonged spawning season during spring and summer (Jordan et al., 1998). In eastern Tasmania, this species spawns over an extended period of at least five months, from October to February, but the bulk of spawning occurs between October and December, with a lower level of spawning activity in the latter half of the spawning period (Jordan et al., 1998; Lyle and Hodgson, 2002). In South Australia, the spawning season is similarly prolonged (e.g. mainly October to March, with limited activity in September and April) (Ye et al., 2002, cited by Jones and Noell, 2005; McGarvey et al., 2006), and there are two spawning peaks (November / December, and February). In South Australia, seasonal variation in the commercial catch and in the lack of spawning fish (in commonly fished areas) suggest that adults might move from fishing areas during the spawning season (Fowler et al., 2008).

H. melanochir are serial batch spawners, with asynchronous oocyte development occurring simultaneously in reproductively active ovaries (St Hill, 1996, cited by Jordan, 1998). Southern Sea Garfish eggs are large; about 2.9 mm in diameter (Jordan et al., 1998).

Experiments in Tasmania have indicated that H. melanochir larvae hatched 28-30 days after fertilisation, and they hatch out as large (7.8-8.5mm) post-flexion larvae (Jordan et al., 1998).

In Tasmania, a sandy area from 2m to 5m deep in Great Oyster Bay was shown to be significant for settlement of Southern Sea Garfish eggs (Jordan et al., 1998). Eggs were mainly attached to drift macroalgae in the bay, but the density of eggs was unrelated to the volume of drift material. Experiments have shown that after fertilisation, H. melanochir eggs become negatively buoyant, which suggests that they sink immediately to the bottom and become attached to vegetation (drift algae, in the case of Great Oyster Bay) by their chorionic filaments (Jordan et al., 1998), which assist adhesions and/or entanglement (Noell and Ye, 2008). In other areas, such as Flinders Island in northern Tasmania (Jordan et al., 1998), and Kangaroo Island in South Australia (Noell, 2005), seagrass may be an important substrate for egg settlement.

In South Australia, there is a significant spatial correlation between the densities of larval Southern Sea Garfish in the water column sampled by plankton nets and the presence of seagrass, particularly in northern Gulf St Vincent (Jones et al., 2002; Noell, 2003, cited by McGarvey et al., 2006). In the gulfs of South Australia, the well-developed larvae hatch from the eggs that are adhesive to seagrasses and drifting filamentous macroalgae. With the aid of wind-driven surface currents, the larvae are entrained in the shallower waters of the South Australian gulfs and sheltered embayments, where seagrasses are the main benthic habitat (Noell, 2004, cited by Jones and Noell, 2005).

Recent modelling of the Southern Sea Garfish populations in the South Australian gulfs suggests regular (3-4 yr) cyclic variation in recruitment (data by McGarvey and Feenstra, cited by Jones and Noell, 2005). A long time series of catch data from both gulfs in S.A. suggests that females may be more abundant than males, and recruit in higher numbers (McGarvey et al., 2006).

Post-larvae or young fish less than 1-year-old live in estuaries from March to July then move to inshore marine waters, remaining there for up to 2 years (Hale and Butcher, 2007, cited by Steer et al., 2008).

Other Information

Predators of H. melanochir include New Zealand Fur Seal Arctocephalus forsteri (Page et al., 2005), and various bird species such as Little Penguin (Klomp and Wooler, 1988; Cannell, 2004; McClatchie and Kendrick, 2007), Crested Tern Sterna bergii (Ward et al., 2008; McLeay et al., 2009); Pacific Gull Larus pacificus (Lindsay and Meathrel, 2008) and Australasian Gannet Morus serrator (Bunce, 2001).

This species can form large schools. H. melanochir tend to school by sex in some areas (Jordan et al., 1998). Garfish school near the surface at night. During the day, they school close to the bottom, often over seagrass beds (Jones and Noell, 2005).

Fisheries Information

Southern Australia - Commercial

Southern Sea Garfish is a significant commercial species across southern Australia, particularly in South Australia (see below). Most catches are taken from State waters, but it is noted that Southern Sea Garfish is a minor reported bycatch in the Commonwealth-managed Southern Squid Jig Fishery (Furlani et al., 2007). Given the shallow depth range of this species, it is possible that the records in the squid fishery are misidentified.

In New South Wales, H. melanochir is reported to be one of the 6 main fish species caught in the Ocean Hauling Fishery (N.S.W. DPI, 2004b, 2006b). This species is reportedly caught along the entire New South Wales coast (BRS maps, 2004), but the accuracy of the data have not been determined, because the range of this species is not known to extend to northern New South Wales. Near the Victorian border, Southern Sea Garfish may be caught by N.S.W. fishers and misreported as Eastern Sea Garfish (Hyporhamphus australis) (Smith, 2002).

In Victoria, Southern Sea Garfish is taken across the State, with various gear types, including beach seine nets. BRR (1991) reported that from 1964/65 to 1984/85, total recorded catches in Victoria ranged between 103t (in 1978/79) and 245t (in 1981/82). During the 1970s and 1980s, the catch from Port Phillip Bay was approx 80-100t per annum, but has since decreased to between 20 and 30t per annum during the mid to late 2000s (NRE Victoria, 2007). The catch from Western Port area has been less than 30t per annum in almost all years since 1980, and less than 15t per annum from the mid 1990s to the mid 2000s. The catch from Corner Inlet has been more consistent over time, and has ranged from 25t to 53t per annum during the 1980s, 18t-75t per annum (but mostly more than 30t) during the 1990s, and 43t to 79t per annum during the early and mid 2000s. The commercial catch (in tonnes live weight) of Sea Garfish in recent years, is as follows (from NRE Victoria, 2002 – 2007; DPI, 2008):

Commercial Catch of Sea Garfish in Victorian Waters 1997 – 2008
Year	Catch (t)
1997/98	90
1998/99	88
1999/00	118
2000/01	125
2001/02	117
2002/03	85
2003/04	84
2004/05	104
2005/06	72
2006/07	81
2007/08	72
(DNRE Victoria, 2002 - 2008); DPI Victoria, 2008b

In Tasmania, BRR (1991) reported that from 1964/65 to 1989/90, total recorded catches of Southern Sea Garfish ranged between 6t (in 1966/67) and 151t (in 1989/90), with catches in the order of 20-40t during most years of the 1970s; 30-50t per annum during the early to mid 1980s, and approximately 70t per annum during the late 1980s. Landings in 1997 were around 87 tonnes, with 70% of the catch taken by beach seine (Lyle, 1998, cited by Jordan et al., 1998). H. melanochir is caught throughout the State, but catches are concentrated along the south-east, east, north and north-east coasts, particularly around Flinders Island (Jordan et al., 1998; Lyle and Hodgson, 2002; Ziegler et al., 2006). Following Flinders Island, the east coast was of secondary importance until 2000/01, but catches have fallen since that time (Ziegler et al., 2006). In the Tamar Estuary, this species was recorded as the 4th most abundant species caught during the mid to late 1990s (Aquenal, 2005). Since 1990s, Southern Sea Garfish production is reported to have remained relatively stable, usually between 70-90 tonnes per annum (except for a low of 56t in 1995/96, and a high in 1998/99, when a total catch of 102t was recorded, including the highest year of catches by dip net, at 34t) (Lyle and Hodgson, 2002; Ziegler et al, 2006). In 2000/01, the total reported commercial catch was 74t, with beach seine catch rates during that year being the highest on record (Lyle and Hodgson, 2002). In Tasmania, H. melanochir is taken by a variety of gear types, with beach seines and dip nets (close to shore, mainly less than 10m) accounting for 80-90% of the annual catch in recent years; much of the remainder is taken by purse seines and spears (Lyle and Hodgson, 2002; Ziegler et al., 2006). Dip-netting is the preferred method in the south-east and east coasts, accounting for around 85% and 70%, respectively, of the total catch in these regions. More recently, purse seining has also been used along the south-east coast. In contrast, north-east coast catches are almost exclusively taken by beach seines (Ziegler et al., 2006). Dip nets are used during the night over shallow areas of sand, seagrass and reef to target surface fish that are attracted to lights. In Tasmania, this species has traditionally been taken by beach seines in winter, although other methods such as lampara / purse seine, push nets and dip nets (the latter especially in summer) have also been used in recent years (Jordan et al., 1998; Lyle and Hodgson, 2002). During the 1990s and early 2000s, beach seine was still the dominant method used. The regional catches differ between years. For example, between the mid 1990s and early 2000s, annual catches from the north-east declined (from around 50t to 27t per annum); east coast catches fluctuated between 13 and 24 tonnes per annum; and south-east coast catches (including Norfolk and Frederick Henry Bays) increased, from 4 tonnes to 20 tonnes per annum (Lyle and Hodgson, 2002). In Tasmania, beach seine and dip net catch rates have been relatively stable during the early and mid 2000s (Ziegler et al., 2006). Sampling of the commercial catch along the east coast of Tasmania from 1995 to 1997 indicated an age range of 1 – 8 year old fish in the catch, with 4 – 5 year olds dominating (Jordan et al., 1998).

Commercial Catch of Sea Garfish in Tasmanian Waters 1990 – 2005
Year	Catch (t)
1990/91	81
1991/92	80
1992/93	82
1993/94	83
1994/95	69
1995/96	56
1996/97	92
1997/98	83
1998/99	102
1999/00	91
2000/01	74
2001/02	~88
2002/03	92
2003/04	66
2004/05	75
(Lyle and Hodgson, 2002; Lyle et al., 2004; Ziegler et al., 2006)

In Western Australia, BRR (1991) reported that from 1964/65 to 1989/90, total recorded catches ranged between 16.6t (in 1969/70) and 49.91t (in 1989/90), with catches in the order of 20-30t during most years from the mid 1960s to the mid 1980s, increasing to 30-40+ tonnes per annum during the mid to late 1980s. H. melanochir is taken by a number of fisheries in Western Australia, including the Cockburn Sound (Fish Net) Managed Fishery, in which it is one of the two main target species. It is also one of a suite of species taken in the Cockburn Sound (Line and Pot) Managed Fishery. Catches of garfish from Cockburn Sound increased steadily in 3-4 year cycles, from 1980 to the end of the 1990s. The annual catch dropped sharply in 1997, but increased again the following year. In 1999, the catch was 36.8 tonnes (Ayvazian and Nowara, in Department of Fisheries W.A., 2000). During the 1990s, this species contributed about 40% of the total commercial finfish catch from Cockburn Sound (Department of Fisheries, W.A., 2000). In 2005, the total finfish catch from Cockburn Sound was 40.4 tonnes, which was the lowest catch recorded since the 1970s. The composition of the 2005 catch included about 13 finfish and elasmobranch species, and around 88% of the total catch consisted of Australian herring (Arripis georgianus) and Southern Sea Garfish, which are caught mainly by netting (Department of Fisheries W.A., 2006). Garfish is also reported to be taken in the Shark Bay Beach Seine and Mesh Net Managed Fishery (Department of Fisheries W.A., 2000). Catches of Southern Sea Garfish from all fisheries in W.A. are shown in the table below.

Reported Catches of Southern Sea Garfish from W.A. waters, 1997-98 to 2006-07
Year	Live weight (kg)
1997/98	47,835
1998/99	75,716
1999/00	45,285
2000/01	27,085
2001/02	31,139
2002/03	33,842
2003/04	41,574
2004/05	38,068
2005/06	34,992
2006/07	31,089
(W.A. Fisheries Research Services Division statistics 1994-2001; W.A. State of the Fisheries reports, 2000/01 - 2007/08)

South Australia – Commercial

Southern Sea Garfish is one of several key species that dominate commercial catches in the Marine Scalefish Fishery in South Australia, and it is fished throughout the State. The annual South Australian catch amounts to more than the combined catch from W.A., Victoria and Tasmania. The bulk of the S.A. catch (~ 95%) is taken in Gulf St Vincent (GSV) and Spencer Gulf (SG), using power haul nets (small mesh), with lesser quantities taken by dab nets (McGarvey et al., 2006; Noell and Ye, 2008; PIRSA, 2008c; Fowler et al., 2008, 2009). Major areas where large tonnages are caught include far northern GSV and northern SG, followed by southern Fleurieu Peninsula, eastern GSV, north-eastern Kangaroo Island bays, eastern and south-eastern SG, and the metropolitan coast of GSV. On the west coast of S.A., Baird Bay is one of the major fishing areas. The catch and effort history differs between the two gulfs, and is discussed in Jones et al. (1990), McGarvey et al. (2006), and Fowler et al. (2007, 2008). Catch per unit effort for haul nets fluctuates, and has been high in some recent years (e.g. 2000/01 and 2005/06) (Steer et al., 2006). Southern Sea Garfish has been fished commercially in South Australia for decades, and there are annual catch data dating back to 1951/52 (Jones et al., 1990). Catches were high during some years of the 1970s and 1980s, and fluctuated between 300t and 650t during those decades. BRR (1991) reported that from 1964/65 to 1989/90, total recorded catches ranged between 260t (in 1970/71) and 652t (in 1981/82), with catches in the order of 300-500t during most years of those 26 years. Catches from 1985 to 2007 are shown in the figure below. The lowest catches since the early 1950s (and very low haul net effort) were recorded in 2006/07 and 2007/08 (Fowler et al., 2007, 2008). In Spencer Gulf, both catch and effort of haul nets and dab nets have displayed a declining trend during the 2000s, whereas catch and effort in Gulf St Vincent has fluctuated significantly over the same period. At a State-wide scale, both catch and effort have declined throughout the 2000s. Market sampling over a long period in South Australia has indicated that female garfish dominate the catch, particularly in summer. In spring to summer, spawning aggregations of females over shallow-water (< 5 m) seagrass beds are targeted with haul nets. Winter catch rates peak at roughly double those of summer, presumably because both females and males are taken, with males harvested only lightly in summer when spawning females are targeted inshore, and these females usually comprise about 85% of the summer catch in both gulfs (McGarvey et al., 2006). Winter haul net catches are also regularly higher, particularly for targeted haul nets in Gulf St Vincent. Dab nets, which account for about 5-15% of the catch, show the opposite seasonality, with most of the catch taken in summer, particularly in Gulf St Vincent (McGarvey et al., 2006). Southern Sea Garfish recruit to the fishery by about 15 months of age, and by age 7 most garfish have died either from natural or fishing-related causes (Jones, 1981; Ye et al., 2002, cited by Jones and Noell, 2005). However, during the past decade the majority of the commercial catches have been 1 and 2 year old fish, with very minor contribution of fishes aged 3 to 5 (McGarvey et al., 2006). The catches from South Australia account for most of the national catch of this species (Fowler et al., 2008).

Southern Sea Garfish that are caught incidentally in the S.A. Rock Lobster Fishery are permitted to be retained for sale (Sloan, 2003a; Sloan and Crosthwaite, 2007). Although catches of several tonnes per annum were made during the 1980s, catches during the 1990s and 2000s were less than 1t per annum (Fowler et al., 2008).

This species is also part of the bycatch in the South Australian pilchard fishery (PIRSA, 2004).

Commercial Catch of Sea Garfish in South Australian 1985 – 2007

(from tables in Knight et al., 2005, 2006, Knight and Tsolos, 2009)

Recreational

A national recreational fishing survey from 2000 to 2001 indicated that “garfish” (more than one species) were taken in all States, with a total estimated harvest of 2.4 million fish or 4% of the national finfish harvest. Catches from South Australia dominated (possibly as high as 62% of the total; with various estimates of 1.2 to 1.5 million fish), with New South Wales, Western Australian and Victorian catches of secondary importance (12%, 11% and 10% of the total respectively). Southern Sea Garfish was the most significant garfish species in the catch, especially in South Australia (Henry and Lyle, 2003). The national recreational fishing survey (Henry and Lyle, 2003), indicated that the majority of the garfish catch (around 72%), was taken in coastal waters; estuary fishing produced about 23% and offshore fishing 5% of the annual catch. Line fishing methods accounted for 95%, and nets about 5% of the harvest. About 70% of the garfish were caught from boats, compared with 30% from shore-based fishing. In South Australia, Garfish was ranked as the third most abundant species taken (14% of total numbers). In South Australia, boat fishers took the largest percentage of Garfish (81%) (Jones and Doonan, 2005). The species accounted for between 2-3% of the finfish harvest in New South Wales, Western Australia and Victoria (Henry and Lyle, 2003). Number of released fish are relatively low (e.g. less than 13% in all southern Australian States for which data we collected, during a survey in 2000: McLeay et al., 2002).

For South Australia, recreational fishers mainly use dab nets and hook and line to catch Southern Sea Garfish. The table below shows results of a national recreational fishing survey (Henry and Lyle, 2003; Jones and Doonan, 2005) indicating catches of “garfish” (mainly H. melanochir) by region. Northern Gulf St Vincent and southern Spencer Gulf dominate the catches. Converting these numbers to weights of garfish, a fishery stock assessment model (“GarEst”: McGarvey et al., 2006), estimated an annual recreational fishing catch in South Australia of 128 tonnes, which represented 20% of the total South Australian garfish catch (16% in Spencer Gulf and 24% in Gulf St Vincent) (McGarvey et al., 2006). Recreational catches in Gulf St Vincent are estimated to have increased since 2000 (McGarvey et al., 2006). In South Australia, fishing for garfish is promoted as being easy in seagrass beds and around jetties. “Dabbing” for garfish (using dab-nets) from boats at night is popular in South Australia (DAFF, 2007). Garfish are also used as bait for fishing Mulloway (Fish SA, 2001).

Recreational Catches of “Garfish” (mainly H. melanochir) by Region in South Australia
Region	No. Caught	No. Released
Northern Gulf St Vincent	552,683	93,951
Southern Spencer Gulf	328,640	34,864
Southern Gulf St Vincent + Fleurieu Peninsula	165,592	9,603
South-Eastern South Australia	148,698	16,147
Coffin Bay	137,083	18,273
Northern Spencer Gulf	132,350	19,671
Kangaroo Island	28,940	4,587
Far West Coast	13,326	394
Mid West Coast	3,770	1,548
(Henry and Lyle, 2003; Jones and Doonan, 2005)

Reported catches of Southern Sea Garfish by the charter boat fishery in South Australia include 2,792 from August 2005 to June 2006; 1,049 in 2006/07; 1,365 in 2007/08 and 5,449 from July 2008 to March 2009, mostly taken from gulf waters (Knight et al., 2007; PIRSA data, 2009).

In Western Australia, the catch of Southern Sea Garfish in 2000/01 was approximately 304,000 fish. In 1997 in W.A., a 12-month survey of recreational boat-based fishing from Augusta to Kalbarri (Sumner and Williamson, 1999), indicated that Southern Sea Garfish was the 7th most abundant species taken, with an estimated ~ 79,000 individuals (= 7.6 tonnes) caught during the survey, and about 4,300 released. Much of the catch was taken in the Perth and Mandurah areas. During another boat anglers’ survey, conducted during 1996/97 in southern Perth waters (including Cockburn Sound), Southern Sea Garfish was the 4th most abundant species taken, in terms of numbers, with an estimated catch of 24,000 (Sumner and Williamson, 1999). Cockburn Sound is a significant area for recreational fishing of garfish, with an estimated catch of about 18t in 2000/01 (WA State of the Fisheries report, 2003/04). Some clubs and associations in WA keep records of the maximum sizes caught (e.g. Lancelin Angling and Aquatic Club Inc. hold a record of a 0.344 kg specimen, caught in 1990).

In Tasmania, garfish are caught by recreational fishers using lines, dip-net, and beach seine (Smith and Heran, 2001).

Garfish are caught recreationally throughout Victoria, with Port Phillip Bay being particularly important for recreational catches (Coutin, 2000). As well as sites in Port Phillip Bay, this species is reported to be eagerly sought in Western Port Bay and Corner Inlet (DAFF, 2007). Some clubs and associations in Victoria keep records of the maximum sizes caught. The Victorian State record is 0.36kg, being a specimen taken from Corner Inlet in 1985 (Australian Anglers Association, 2005).

Other

Southern Sea Garfish is one of the nearshore scalefish species that is utilised by coastal Aboriginal groups in South Australia.

Vulnerable Characteristics of the Species

Southern Sea Garfish is a schooling species, particularly over shallow seagrass beds, and is readily captured by line fishing and netting methods. It is highly sought-after by recreational and commercial fishers, and populations across the range are heavily targeted.

Because Garfish is a schooling species, catch rates (CPUE) are considered to be neither reliable nor sensitive indicators of abundance trends (Lyle and Hodgson, 2002; McGarvey et al., 2006). It is possible that model and CPUE measures of biomass trend can underestimate the decline in overall population size. Catch rates can decline less slowly than the total spatial extent of schools, as fishers target the remaining aggregations in which densities remain more nearly constant (McGarvey et al., 2006).

Southern Sea Garfish is a “delicate” fish. Prospects for survival are low for garfish that are hooked or netted, handled and released. In 2002, State and territory fisheries agencies ranked the species most likely to experience low survival on release after being hooked, and Southern Sea Garfish was ranked in the top 10 species in both South Australia and Victoria (McLeay et al., 2002). Anecdotal information suggests that most Garfish are caught in the mouth; smaller numbers are hooked in the beak or throat, but gut hooking is rare. Survival issues for Garfish include deep-hooking, scale loss (e.g. from handling of fish), and predation after release (FRDC, Recfish Australia and Infofish, 2008).

Stock assessment modelling in South Australia has indicated that recruitment is highly variable over space and time, and may be low for a succession of years (e.g. garfish spawned during summers of 2000/01 and 2002/03) (McGarvey et al., 2006) Recruitment also varies between gulfs (e.g. well below average in Spencer Gulf in 2004, yet very high in Gulf St Vincent during the same year) (McGarvey et al., 2006). Although the accuracy of the recruitment estimates is uncertain (McGarvey et al., 2006), the possibility of highly variable recruitment over small spatial scales, and over time, increases the vulnerability of stocks at local scales to over-exploitation and depletion.

There are few fishable age classes of Southern Sea Garfish, and available age classes are heavily fished both commercially and recreationally from the time of first recruitment.

Threatening Processes

In areas where this species is heavily fished, fishing is the main threatening process.

In South Australia, Southern Sea Garfish was previously classified as fully fished (DEHAA and EPA, 1998; Ye, 1999; MSFMC, 2003), according to available biological performance indicators (e.g. Ye, 1999; Ye, cited by Anonymous 2001b; Jones et al., 2002). It is now classified by government as over fished (Noell et al., 2005; PIRSA, 2007) in South Australia. Indications include a significant decline in catches during the early and mid 2000s; a drop in biological performance indicators, and results from stock assessment modelling (PIRSA, 2007), as discussed below. During the mid 2000s, limit reference points (that trigger management action) were reached for yearly model-based estimates of recruitment, egg production (less than 20% estimated for each gulf), legal-size stock biomass, and harvest fraction (McGarvey et al., 2006).

Catch records have indicated that the fishery in South Australia had sustained substantial catches of garfish for at least 60 years. However, exploitation rates for the modern fishery, estimated using a complex fishery simulation model, have generally exceeded 50% of the fishable biomass (and may have been as high as 67% in Gulf St Vincent during the past 5 years (McGarvey et al., 2006; Fowler and McGarvey, 2007). In 2005, estimated harvest fractions (exploitation rates) were extremely high by international standards, the fishery removing 62% of legal biomass in Spencer Gulf and 73% in Gulf St Vincent (McGarvey et al., 2006). The South Australian exploitation rates reported to be much higher than any other exploited species in South Australian waters, and higher than garfish in other Australian States. The rates are approximately twice the generally accepted safe upper limits for sustainable harvest, and are roughly double the limit reference point for this indicator (of 32%) (McGarvey et al., 2006). The fishery in South Australia relies heavily upon continued high levels of recruitment, and catches (and by inference, population structure) are now dominated by young (1 and 2 year old) fish, with few individuals from the 3+ to 5+ age classes (McGarvey et al., 2006; Fowler et al., 2008). However, during the past decade, recruitment levels have mainly been low, with the lowest ever recruitment estimated to have occurred in Spencer Gulf during the early 2000s, and low levels were also estimated for Gulf St Vincent at that time, followed by a high recruitment in that gulf in 2004 (McGarvey et al., 2006). The heavy fishing over a long period has reportedly resulted in recruitment over-fishing, biomass reduction, and “population truncation”, with few age classes remaining in the population (Fowler and McGarvey, 2007; Fowler et al., 2008). In South Australia, sampling in 2005, in which population age structures were compared for the months July-September 1997-99 with 2005, indicated a reliance of the fishery in that year on 1 year old fish in both Spencer Gulf and Gulf St Vincent. In comparison, in 1997-99, 2 year old fish dominated the catch in Gulf St Vincent. Evidence is based on results of market sampling and fish ageing in 2005/06, compared with similar sampling in 1954/55, and also sampling of a lightly fished population during the 1980s (Jones, 1990) (Fowler and McGarvey, 2007). The truncation of age structure increases the vulnerability of the stock to decline, if the fishery is reliant on the strength of a single year class (or two year classes) to persist, particularly if recruitment strength is variable from year to year due to environmental causes. Also, heavy fishing of a single, young year class is not a conservative fishing strategy, because spawning stock biomass has been fished down over time, and little remains to perpetuate the population, or the fishery.

In South Australia, it has been reported that Southern Sea Garfish now mature at a smaller size than was observed 40 years ago, believed to be a response to heavy fishing levels (Ye, 1999; Ye, cited by Anonymous, 2001c).

The distribution and life history of Southern Sea Garfish are closely associated with intertidal and shallow subtidal seagrass beds (McArthur et al., 2003; Noell, 2004, cited by Jones and Noell, 2005). In a study of the catch distribution across South Australia, three areas separated by hundreds of kilometres produced the highest catches, and these relatively protected areas support extensive beds of intertidal and subtidal seagrasses (Fowler et al., 2008). Issues include the impact of pollution (e.g. effluent discharges, bringing excess nutrients, sediments and heavy metals), dredging (also causing sedimentation, and physical damage to seagrass beds) and coastal development on the seagrass habitat of this species. Southern Sea Garfish, particularly juveniles, may be vulnerable to impacts from coastal dredging (EPA Victoria, 2001). Processes that reduce the quality and extent of seagrass cover are considered to be significant threats in a number of States (Roob et al., 1998; New South Wales Fisheries, 2003d). In South Australia, many of the most significant seagrass beds in which Southern Sea Garfish occur, are subject to numerous impacts from pollutants, particularly nutrient-rich effluent, and sediment from diffuse source discharges, and coastal developments (see Baker, 2004, for summary, including history of seagrass decline in Gulf St Vincent).

In South Australia, many of the estuarine areas in which early juvenile Southern Sea Garfish are found, are subject to numerous impacts from pollutants, and other forms of habitat degradation – see, for example, Baker (2004), for discussion of such impacts in northern Gulf St Vincent, and parts of Spencer Gulf.

Barriers to migration within estuarine systems may interrupt the life cycle of this species. Higham et al. (2002) reported that closure of the Murray Mouth may affect this species, by interrupting aspects of its life cycle, with short term implications for populations. Closure of the Murray Mouth happens periodically, due to the many impediments that restrict natural seaward flow, and exacerbate the build-up of sand at the Mouth.

In South Australia, Victoria and Tasmania, southern Sea Garfish has been ranked as one of the 10 top species in terms of susceptibility to catch and release mortality (McLeay et al., 2002). In South Australia, mortality of undersized Sea Garfish that are caught and released is assumed to be substantial (McGarvey et al., 2006), but this additional mortality is not considered in management models. Therefore, fishing effort in South Australia, although high already, may be even higher than estimated.

Sea level rise due to climate change may impact coastal seagrass habitats that are important as breeding or nursery areas, and this may adversely affect Southern Sea Garfish populations (Matear et al., 2008).

Research Notes

In South Australia, examples of research on Southern Sea Garfish include (i) study of the species biology (e.g. growth / size at age, and reproduction – the latter including spawning cycle, length at maturity, sex ratios and batch fecundity estimates) (Jones, 1990; Ye, 1999; Ye and Short, 2000; Ye et al., 2002a,b; Noell, 2004; Fowler et al., 2008); (ii) biological parameters, based on extensive samples of garfish catches by age and length (Jones et al. 2002); (iii) the habitat ecology of larval and juvenile garfish; and linkages between the distribution of seagrass and garfish larvae in Gulf St Vincent (Jones et al, 2002; Noell, 2004); (iv) population dynamics, demography and spatial distribution (e.g. Fowler et al., 2008); (v) a study of larval development of Sea Garfish and River Garfish in S.A. (Noell, 2003); (vi) genetic discrimination between stocks in the southern States (Donnellan et al., 2002); (vii) molecular discrimination of garfish larvae in southern Australian waters (Noell et al., 2001); and (vii) seasonal variation in diurnal feeding patterns (project by J. Earl, Flinders University, 2009).

A recent project has examined the stock structure and movement of H. melanochir throughout South Australia waters. The project utilised otolith trace element analysis, stable isotope analysis and shape analysis to infer age-related patterns of movement, delineate potential sub-populations, and to determine the extent of mixing within South Australian coastal waters (Steer et al., 2009). Results have assisted in determining how key fishing areas around the State are replenished. Combined results have so far indicated that the population structure of Southern Sea Garfish is more complex than was previously assumed (e.g. in terms of movements and mixing), and that stocks can be discriminated at a much finer spatial scale (Steer et al., 2009).

In South Australia, an age-structured stock assessment model to assist management of the Southern Sea Garfish fishery has been developed, based on biological data collected (growth, age composition, reproductive biology), combined with a catch and effort time series. The fisheries stock assessment model (“GarEst”) provides estimates for yearly recruitment, legal biomass and harvest fraction from the stock in each gulf (McGarvey and Feenstra, 2004; McGarvey et al., 2006).

Market sampling of Southern Sea Garfish, to obtain data on fish length, age and reproductive state, has been undertaken regularly in South Australia during the 1990s and 2000s (McGarvey et al., 2006).

At University of Adelaide, a student project was being undertaken during 2008-09 on parasites as potential stock indicators for Southern Sea Garfish (research by E. Brock, K. Hutson and M. Steer).

Research Recommendations

In Tasmania, more information is required on critical habitats for the life stages (Lyle and Hodgson, 2002).

In South Australia, more information is required on the location of critical spawning and egg-laying areas.

Recreational catches (over space and time) as a proportion of total catch should be better quantified in all southern Australian States.

Management Notes

There is a Commonwealth government-sponsored information sheet on best practices for releasing undersized garfish to limit mortality and enhance survival. Recommendations include using long-shank hooks in larger sizes (e.g. 8 or 10), and methods of unhooking the fish that minimise damage and scale loss (FRDC, Recfish Australia and Infofish, 2008).

Some States do not specify a minimum legal size for garfish, in recognition of the low survival rate of caught and released garfish (S. Morison, MAFRI, pers. comm., cited by McLeay et al., 2002; FRDC, Recfish Australia and Infofish, 2008).

In W.A., there are mesh size regulations for the taking of garfish, in the Shark Bay Beach Seine and Mesh Net Managed Fishery (Department of Fisheries, Western Australia, 2000).

In South Australia, where haul nets take the majority of the commercial catch, fishing activities are generally restricted to waters of less than 5m depth (periodic exemptions for deeper water fishing were revoked in 2006), and 3cm mesh size is used on nets (McGarvey et al., 2006). A licence amalgamation scheme was implemented in the early 1990s, to reduce the number of commercial Marine Scalefish Fishery licence holders in the fishery by about one half (Fowler, 2005, cited by McGarvey et al., 2006). More recently in South Australia, a net buy-back scheme (i.e. permanent reduction in the number of net endorsements) and spatial closures to net fishing were implemented in June-July 2005 (McGarvey et al., 2006). Of 113 marine scalefish net licence holders, 61 (54%) accepted the buy-back offer and their endorsements were rescinded. Of the 61 acceptances, 37 fishers surrendered their net entitlements but retained the licence to fish by line or shark net, and 24 net fishers surrendered their entire net licence and left the commercial fishery (McGarvey et al., 2006). Regarding spatial closures, recent netting closures include almost the entire coastline around Yorke Peninsula, as well as much of northern Spencer Gulf; south-western Spencer Gulf; bays of the west coast / eastern Great Australian Bight; a number of bays along the mid west coast; around the bottom of Eyre Peninsula, and some of the bays in north east Kangaroo Island. Commercial net fishing effort is reported to have been reduced by 47% since the buy-back scheme and the closures, compared with figures from the early 2000s.

The South Australian Marine Scalefish Fishery (in which Sea Garfish is one of the key species) is an effort-managed fishery with limit reference points and general performance indicators in place. Computer-based fishery assessment models have been developed for garfish (PIRSA, 2008b) (see Research Notes). In South Australia, the possible “population truncation” related to fishery exploitation has prompted a stock rebuilding program (Fowler et al., 2008).

In the commercial fishery in South Australia, there is (i) a limited number of net endorsements in northern Gulf St Vincent to harvest in waters >5 m depth; and (ii) a limited number of licence endorsements permitted to use dab nets (PIRSA, 2008c).

In Tasmania, there are licence restrictions for beach seine nets (Smith and Heran, 2001), but not for dip nets (since all holders of scalefish licences have access to dip nets). Concern has been expressed about the potential for significantly increased effort using dip nets (Smith and Heran, 2001; Lyle and Hodgson, 2002), and there are examples of this occurring in recent years (e.g. following introduction of a management plan), to the extent that catch and effort management indicators were triggered. Although it is not known whether present catch levels are sustainable, it has been recommended that management options to limit further expansion of the garfish fishery be considered in Tasmania (Ziegler et al., 2006).

In South Australia, the legal minimum length for H. melanochir is currently 23 cm, measured from the foremost part of the upper jaw to the end of the tail fin (Fisheries Management [General] Regulations 2007 - Schedule 2). The previous size limit (prior to 2001) was 21cm. The bag limit is 60 per person (previously 80) and boat limit is 180 per boat (previously 240) (PIRSA, 2008b,c). In South Australia, the minimum mesh size for haul nets has not been altered, and remains at 3cm. Selectivity studies by Jones (1982) showed that a 3.2-cm mesh size could permit escapement of most undersized Garfish in the range 21-23 cm, but most are captured by a 3cm net (McGarvey et al., 2006).

In Tasmania, there is a size limit of 25cm measured from the upper jaw to end of tail, a recreational possession limit of 30 garfish (DPIW Tasmania, 2008). The previous possession limit was 45 (Smith and Heran, 2001).

Management Recommendations

In Tasmania, it has been recommended to prohibit commercial fishing in areas where there are substantial seagrass beds, in an effort to help preserve stocks (Smith and Heran, 2001).

Throughout southern Australia, measures to reduce the capture of small, immature Garfish are recommended (e.g. increasing mesh size for nets, and possibly spatial prohibitions in shallow waters where juveniles are prevalent).

Results from recent research (in which otolith chemistry was used to infer age-related patterns of movement and delineate potential sub-populations of H. melanochir in South Australia) suggested that assessment and management of the fishery should be restructured to align with smaller spatial units; e.g. 6 regional components (Steer et al., 2009).

Other Information

Examples of Aquatic Reserves in South Australia which are significant for this species include Barker Inlet (Jones, 1984).

Examples of marine parks and sanctuaries in Victoria in which this species has been recorded include Yaringa, French Island, Port Phillip Heads, Churchill, and Corner Inlet (Plummer et al., 2003; Edmunds et al., 2003).