© 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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Australian Handfish / Australian Spotted Handfish / Common Handfish

Family Name:	Brachionichthyidae
Scientific Name:	Brachionichthys australis Last, Gledhill and Holmes, 2007
Recommended Status in S.A:	Data Deficient
Rationale:  The Australian Handfish is included here because (i) it is a slow-moving, benthic fish (and therefore has a strong site association and limited mobility), and, like other members of the genus, possibly has low reproductive potential and restricted larval dispersal. All of these characteristics increase the vulnerability of handfishes to localised impacts, and population decline; (ii) South Australia is at the edge of the geographic range, and to date, there are very few specimens known from S.A.; (iii) it is taken as bycatch in a number of trawling and dredging operations, in some parts of southern Australia, and although localised population impacts might have occurred (and might still be occurring), no data are available; and (iv) there have been documented declines in populations of other handfishes in southern Australia, hence the vulnerable characteristics of species in this family must be considered. Future surveys are required to assist in better determining the relative abundance and depth range of this species within South Australia. The broad geographic distribution and depth range, as well as the lack of evidence for fisheries bycatch being a threatening process, resulted in the recommended classification of Least Concern at a national level (Pogonoski et al., 2002). However, the site-specific nature and limited dispersal of handfishes would prevent populations in different areas from mixing, and each population might be of naturally low abundance. Therefore, specific processes at a State level could threaten localised populations. An assessment is required of the relative abundance or rarity of this species in S.A., and the collection and analysis of trawl bycatch and other relevant data are also warranted before an adequate assessment can be made at State level.

Page Contents

Current Conservation Status

Pogonoski et al. (2002) suggested Lower Risk - Least Concern, on an Australia-wide basis.
Australian Society of Fish Biology 2001 list: Lower Risk - Least Concern

Distribution

Southern Australia

Brachionichthys australis is the most widespread species in the family, ranging from southern Queensland (e.g. Stradbroke Island) to northern, eastern and south-eastern Tasmania; South Australia, and as far west as Middini Beach in the Great Australian Bight, W.A. (Last et al., 2007; Last and Gledhill, 2009).

Many of the known specimens come from trawls off the central and southern New South Wales coast, and Victoria (Last and Gledhill, 2009).

South Australia

To date, there are very few records from South Australia.

Six specimens of Handfish, reported to be this species of Brachionichthys, have been collected by benthic sled, between 160m and 166m deep, in the Murray Canyons area south of Kangaroo I. (AUSCAN voyage data, South Australian Museum data, 2003, cited by T. Bertozzi, S.A. Museum, pers. comm., 2005 and R. Foster, S.A. Museum, pers. comm., 2006).

There are recreational diving records of handfish from northern Kangaroo I. (recorded by J. Thistleton, cited by Muirhead, 1997); however it is not known for this report whether the species sighted was Australian Handfish or Warty Handfish (see following synopsis).

It is noted that during a survey in 2002, a handfish (incorrectly reported to be the endangered Tasmanian species Spotted Handfish B. hirsutus) was recorded in the Section Bank area, near the mouth of Barker Inlet in north-eastern GSV (Cheshire et al., 2002). The Spotted Handfish does not occur in S.A., and it is not known whether or not the specimen was Australian Handfish (which, superficially, is similar in appearance to B. hirsutus), a Warty Handfish (see synopsis), or an undescribed species. The shallow depth (less than 20m) of the specimen is noted here.

Habitat

Habitat information from Pogonoski et al. (2002), Australian Museum (2003d), and Last et al. (2007): Brachionichthys australis is rarely seen in shallow water, and is usually seen in the catches of trawls taken at depths between 40m and 100-150m (Kuiter, 1993; Australian Museum 2003d; Last et al., 2007). The currently published depth range is 18m to at least 210m, but may occur deeper (Last et al., 2007).

There is very little information about the habitat, apart from Last et al.’s (1983, cited by Pogonoski et al., 2002) statement that the species lives on soft muddy or shelly substrates.

Notes on the Biology

Growth

Brachionichthys australis grows to about 8cm in length (Hutchins and Swainston, 1986; Last, in Gomon et al., 1994; Australian Museum, 2003d). Last et al. (2007) reported that the species attains at least 63.5 mm SL, commonly 35–50 mm SL, and the smallest specimen examined was 13.4 mm SL. Early juveniles resemble adults in body shape (Last and Gledhill, 2009).

There is no information on age-related growth for this species; however, the closely related species Brachionichthys hirsutus grows rapidly to 3–5 cm SL by the first year, and to 7–8 cm SL the second year. After two years the growth rate slows to only a few millimetres annually (Bruce et al., 1997, 1999; Last and Bruce, 1997, cited by Pietsch and Kenaley, 2005).

Diet

The species probably eats small invertebrates, such as worms, molluscs and crustaceans (Kuiter, 1996b, cited by Pogonoski et al., 2002).

Reproduction

No published information is available on reproduction in this species, but detailed observations have been made for other members of the genus, such as Brachionichthys hirsutus (Bruce et al., 1997, 1999; Last and Bruce, 1997, cited by Pogonoski et al., 2002 and Pietsch and Kenaley, 2005). The Tasmanian Brachionichthys spawn in early to mid spring, following courtship displays between males and females. Fertilisation is external, but it is not known if a single or multiple males fertilize the eggs of individual females in the wild. Egg masses of 80-250 large eggs (connected by a series of fine tubules and tendrils) are spawned on the bottom, around an isolated semi-rigid vertical object, such as an attached benthic animal (e.g. sea squirt) or plant (e.g. green macroalgae). The female remains with the egg mass for seven to eight weeks until hatching. Handfishes lack a pelagic larval stage, and hatch fully formed juveniles (6–7 mm SL) in late spring (November) that fall directly to the sea floor and remain near the spawning site (Bruce et al., 1997, 1999; Last and Bruce, 1997, cited by Pietsch and Kenaley, 2005).

In the closely related species B. hirsutus, females reach maturity after 2-3 years (Bruce et al., 1997, 1999; Last and Bruce, 1997, cited by Pietsch and Kenaley, 2005).

Other Information

Brachionichthys australis belongs to a family of small, benthic fish with “hand-like” pectoral fins, used for walking along the sea floor.

Fisheries Information

The species is caught as bycatch by trawling and dredging (including frequent capture by scallop dredges) in some areas of south-eastern Australia, usually at depths between 40m and 100m – 150m (Kuiter, 1996a; Pogonoski et al., 2002; Australian Museum, 2003d; Last et al., 2007). It is occasionally caught by trawlers and Danish seiners (Last et al., 2007), but it is noted that the species was not reported in Commonwealth reports of bycatch in the South East Trawl Fishery (Wayte et al., 2004) or the Great Australian Bight Trawl Fishery (Brown and Knuckey, 2002).

Brachionichthys australis is caught frequently as bycatch by scallop dredges, and occasionally by trawlers and Danish seiners (Last et al., 2007).

The Australian Handfish is recorded as a non-target catch in the Bass Strait Central Zone Scallop (BSCZS) Fishery, but because this is a widespread species, reports from the 1990s considered the species not to be endangered or vulnerable due to that activity (Harris and Ward, 1999, cited by AFMA, 2002f). There is little information on the amount of non-target catch taken in the BSCZS fishery, because there was no provision for recording by-catch data in logbooks until 2000. Since that time, when a revised logbook that provides for the recording of bycatch information came into use (August 2000), there has been little fishing in the BSCZS fishery (due to the fishery being over-fished previously), hence published and recent bycatch data are still lacking (AFMA, 2002f).

Vulnerable Characteristics of the Species

Generally, adult and juvenile handfishes are largely sedentary; these shallow-water species are known to have small, distinct and measurable populations over small ranges; they have low fecundity; they rely upon benthic structures for nesting, and have a high degree of parental care of the eggs, fully formed young at hatching (i.e. no larval phase), and poor dispersal capability. Handfishes are slow to expand their range and colonise new areas. The shallow-water species found in estuaries and associated channels are particularly vulnerable to site-specific impacts.

The strong site association, low reproductive potential and restricted larval dispersal, are characteristics that increase the vulnerability of these fishes to population decline (Pogonoski et al., 2002).

Threatening Processes

Commercial fishing (i.e. trawling and dredging, where it is occasionally taken as bycatch) is the only identified threat to this species (Pogonoski et al., 2002). The species is usually seen in the catches of trawls taken at depths between 40m and 100–150m (Australian Museum, 2003d; Last et al., 2007).

Sand, mud and shell soft bottom substrates appear to be important to this benthic, site-associated species (Last et al., 1983; Pogonoski et al., 2002; S.A. Museum records). It is currently believed that all handfishes require benthic structures around which to lay their eggs (Commonwealth of Australia, 2004). Therefore, any processes (such as trawling and dredging) that degrade the quality of critical habitat for this species may impact on existing populations, and also threaten future generations of handfish, by reducing reproductive success.

Research Recommendations

Data should be collated for all specimens of handfish collected or photographed in South Australia, and the specimens should be examined and identified by experts (e.g. CSIRO, Hobart).

All prawn trawl fisheries in South Australia (Gulf St Vincent, Spencer Gulf and eastern Great Australian Bight) should record the presence of any handfish species (with location and depth data) when specimens appears in bycatch. Similarly, all benthic fish trawls across the geographic range should record the presence of this, and any other handfish species.

Records of Brachionichthys in shallow waters should be investigated, to determine whether the Australian Handfish has a broader depth range that currently published, or whether there is a third species of handfish present in South Australia. More information is required on the distribution and habitat of this species, across the range.

Further research is needed on the biology and ecology of this species (Pogonoski et al., 2002). In particular, there is little information on growth, longevity and reproduction of this species, and it is not known whether the life history is similar to that of other members in the genus.

Management Recommendations

Measures to reduce the bycatch of this species in benthic trawls and dredges should be encouraged.

Dredging operations (including those in South Australia – e.g. see Fairhead et al., 2002a, 2002b; Cheshire et al., 2002) should be conscious of the potential presence of handfish species, and the possible population impacts on these strongly site-associated benthic species.

Where possible, measures to reduce the bycatch of Australian Handfish in scallop dredges in Tasmania are recommended.

Other Information

Pogonoski et al. (2002) suggested that there is no evidence of any declines for this species, and it may be afforded better protection than other handfishes, due to its more widespread distribution, and occurrence in deeper offshore waters (usually more than 40m and to at least 150m, although the species has been recorded at shallower depths – e.g. 24m).

The taxonomy of handfishes has been revised by P. Last and D. Gledhill at CSIRO (2009). Brachionichthys australis has been frequently misidentified in museum collections as its micro-endemic relative B. hirsutus (a Tasmanian endemic) (Last et al., 2007).

B. australis appears to be reasonably abundant across its range, and was once sympatric with the now rare B. hirsutus in D’Entrecasteaux Channel, off south-eastern Tasmania (Last et al., 2007).

Some morphological differences exist in populations of B. australis, and a molecular study of populations across the range of B. australis may provide evidence of additional species (Last and Gledhill, 2009).

Support for S.A. Listing:

Graham Edgar (University of Tasmania) and Barry Hutchins (ex-W.A. Museum).