© 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 Pygmy Blindfish

Family Name:	Bythitidae
Scientific Name:	Dactylosurculus gomoni Schwarzhans and Moller, 2007 (prev. Ogilbia sp., in Gomon et al., 1994)
Recommended Status in S.A:	Data Deficient
Rationale:  The Southern Pygmy Blindfish is included here because (i) members of the family are viviparous (bear live young), and therefore reproduce at a local, site-associated level; (ii) the species is presumed to have low fecundity and low dispersal ability, and these characteristics can increase the vulnerability of populations to processes that cause decline; and (iii) the species is reported to be found in shallow coastal reef habitats (less than 25m) and also estuaries, and may therefore be vulnerable to coastal marine impacts, particularly in estuarine habitats; (iii) there are very few records of this undescribed species, if it can be assumed that the Southern Pygmy Blindfish is not the same species as Monothrix polylepis, from south-eastern Australia; and (iv) very little is known of the biology, population dynamics or ecology of this small fish species.

Page Contents

Current Conservation Status

No listings known

Distribution

Southern Australia

The species has a southern Australian distribution, from at least Port Phillip Bay in Victoria, to the Recherche Archipelago and Cape Naturaliste in W.A. (Gomon, in Gomon et al., 1994; Kuiter, 1996b; Hutchins, 2005; Schwarzhans and Moller, 2007).

South Australia

Dactylosurculus gomoni was previously misidentified as Monothrix polylepis (Ogilby, 1897), a New South Wales species (Kuiter, 1996b; Schwarzhans and Moller, 2007).
Previously collected specimens from S.A. were assigned to Monothrix polylepis (Paxton et al., 1989; OZCAM database, 2007). Examples of locations where the species (as M. polylepis) has been collected in S.A. include upper eastern Spencer Gulf (e.g. Tickera area) and other parts of Spencer Gulf (e.g. Port Lincoln area, and other locations); northern and eastern Kangaroo Island, and Cape Jervis area at the bottom of the Fleurieu Peninsula (Australian Museum records, cited in OZCAM database, 2007; Schwarzhans and Moller, 2007).

Habitat

The species occurs in shallow, protected rocky reefs, and beneath ledges and under rocks, at depths of less than 25m (Gomon, in Gomon et al., 1994; Kuiter, 1996b; Hutchins, 2005).
The species has also been recorded from estuaries, and often in muddy habitat (Kuiter, 1996b).
Many of the museum records are from shallow subtidal waters (e.g. less than 5m) (Schwarzhans and Moller, 2007).

Notes on Biology and Behaviour

Growth

The Southern Pygmy Blindfish grows to around 6cm (Gomon, in Gomon et al., 1994).

Other Information

The species is rarely seen; has cryptic habits, and is well hidden in its habitat (Gomon, in Gomon et al., 1994).
Like other blindfishes, the species likely has poor eyesight, but has a well developed system of taste and smell, as indicated by the greatly modified lip structure (Gomon, in Gomon et al., 1994). The Southern Pygmy Blindfish has a large, slightly oblique mouth, with row of small teeth in the jaws. The lower jaw is slightly larger, and depressible. The head has various small sensory pores and papillae, and the lips and chin are sculptured, with flaps and pores (Kuiter, 1996b).

Reproduction

Members of the family are viviparous (bear live young) (Breder and Rosen, 1966, cited in Froese and Pauly, 2007; Nielsen et al., 1999); fertilisation is internal, and the males have clasper organs (Gomon, in Gomon et al., 1994).
Based on the mode of reproduction, the species is assumed to have low fecundity (Froese and Pauly, 2007).

Vulnerable Characteristics of the Species, and Threatening Processes

Members of the family are viviparous (bear live young), and therefore reproduce at a local, site-associated level, and presumably have low dispersal ability, characteristics that can increase vulnerability to processes causing population decline.
The species is reported to be found in shallow coastal waters (less than 25m) and also estuaries, and may therefore be vulnerable to coastal impacts in some areas. Estuaries are often subject to many pollutants, and other impacts that degrade water quality and habitat. Polluted estuarine areas can take a long time to recover as toxicants accumulate in their sediments (Pogonoski et al., 2002). There are few pristine or near pristine estuaries remaining in South Australia and most are subject to numerous impacts (see Bucher and Saenger, 1989; Lewis et al., 1998; Barnett, 2001; GeoScience Australia, 2001; Baker, 2004).

Research Requirements

There is little information on the relative abundance of the Southern Pygmy Blindfish across the range, including S.A., because so few specimens have ever been recorded or collected.
Very little is known of the biology, population dynamics or ecology of this species.