© 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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Twospot Fringedfin Goby / Twospot Goby / Twospot Eviota 

Family Name:	Gobiidae
Scientific Name:	Eviota bimaculata Lachner and Karnella, 1980
Recommended Status in S.A:	Possibly Rare D(i) or E(ii) (for S.A. only)
Rationale:  The species is included because (i) E. bimaculata is a little known, sub-tropical species, with a limited reported distribution in South Australia, being known from the western Eyre Peninsula / eastern Great Australian Bight area; (ii) the species is found over a narrow depth range in upper continental shelf waters; (iii) to date, it has been recorded in very low numbers in S.A., but it is not known whether the species is naturally rare in S.A., or recorded numbers are so low due to lack of targeted sampling for very small, cryptic fishes; and (iv) gobies are typically benthic nest spawners and egg guarders, and hence populations may be vulnerable to localised impacts.

Page Contents

Current Conservation Status

(no listings known)
 

Distribution

Australia

The species is considered to be sub-tropical (Hutchins, 2005), and is reported to occur in south-western Australia, with Ceduna on the west coast of S.A. as the recorded eastern limit (Hutchins and Swainston, 1986; Hoese and Larson, in Gomon et al., 1994), and North-West Cape in W.A. as the western limit (Lachner and Karnella, 1980; Hutchins and Swainston, 1986).
There are various specimens in Australian Museums, mostly collected from the central to southern W.A. coast, within the geographic range from Shark Bay down to Augusta.
In W.A., the species is very abundant between Rottnest Island and Shark Bay (B. Hutchins, W.A. Museum, pres. comm., 2007). On the southern coast of W.A., it is more difficult to find, other than at the Recherche Archipelago (B. Hutchins, W.A. Museum, pres. comm., 2007).
  

South Australia

There are very few verified and registered South Australian records of this species, with examples including specimens collected from the Smoky Bay / Ceduna area in the eastern Great Australian Bight. (Australian Museum record I20215001; CSIRO Marine Research records B 2703 and B2704, cited in OZCAM database, 2007).
Survey records from other parts of S.A. could not be found for this report.
 

Habitat

The species is found around rocky reefs and coral reefs (Hoese and Larson, in Gomon et al., 1994). At the Recherche Archipelago and mainland bays in south-western Australia, E. bimaculata has been recorded on rocky reefs (Hutchins, 2005).
The full depth range has not been recorded, but it is noted that there are records from the shallow subtidal to at least 17m deep (B. Hutchins, W.A. Museum, pers. comm., 2007).
 

Notes on the Biology

To date, 2.5cm is the recorded maximum size, and E. bimaculata is one of southern Australia’s smallest fish species (Hutchins and Thompson, 1983; Hoese and Larson, in Gomon et al., 1994).
 

Vulnerable Characteristics of the Species and Threatening Processes

In South Australia, the Twospot Fringedfin Goby is currently known only from a limited geographical area (far west coast / eastern Great Australian Bight region).
The species is found over a narrow depth range in upper continental shelf waters.
To date, this sub-tropical species has been recorded in very low numbers in S.A., but it is not known whether the species is naturally rare in S.A., or recorded numbers are so low due to lack of targeted sampling for very small, cryptic fishes.
Gobies are benthic nest spawners and egg guarders, population characteristics that increases their vulnerability to site-specific habitat impacts.
 

Research Requirements

Both the distribution and relative abundance of this species in South Australia are not well known. The species is very small, and likely to be easily missed in surveys. Those undertaking future surveys of shallow reef areas on the west coast of South Australia (and in other warmer water regions of the upper continental shelf in S.A.) should be conscious of the potential presence of small goby species such as E. bimaculata, and such species should be recorded when found.    
When the less commonly known goby species are recorded in surveys, fish taxonomy experts should be sought to provide species-specific determinations.