Bluespot Goby, Pseudogobius olorum (Sauvage 1880)

Other Names: Blue-spot Goby, Blue-spotted Goby, Galway's Goby, Southern Goby, Swan River Goby, Western Blue-spot Goby

Summary:

A mottled pale brown to yellowish-brown goby becoming whitish below, with 5-6 darker blotches along the back, a series of midlateral blotches, often a blue margin on the anal fin, and a blue spot on the rear of the first dorsal fin of males. Bluespot gobies have a rounded head with bulbous cheeks, and a small inferior mouth (snout tip slightly in front of the jaws).

Cite this page as:

Bray, D.J. & Gomon, M.F. 2022, Pseudogobius olorum in Fishes of Australia, accessed 19 Apr 2024, https://fishesofaustralia.net.au/home/species/151

Bluespot Goby, Pseudogobius olorum (Sauvage 1880)

More Info

Distribution	Gulf St Vincent and Kangaroo Island, South Australia, to the Murchison River, Western Australia. Inhabits shallow estuarine to freshwater areas to hypersaline lakes, including the estuaries of rivers, streams and mangroves, at depths of 0-3 m. The species occur some distance inland in freshwater situations, especially where secondary salinization has occurred following land clearing.
Features	Dorsal fin VI + I, 7-9; Anal fin I, 7-8; Caudal fin (segmented rays) 16; Pectoral fin 14-17; Pelvic fin I, 5; Vertebrae 10 + 15-17 Body slender. Head of moderate size 3.3-4.0 in SL. Snout rounded in side view, extending forward before anterior tip of jaws. Cheeks bulbose. Interorbital narrow, about half eye diameter or less. Mouth small, almost horizontal, reaching to below middle of eyes; lips thin to almost absent; tongue tip truncate. Pore above front of each eye, one behind upper quarter of each eye, and one behind middle of each eye; no fine villi on head; no preopercular pores. Body scales ctenoid, lateral line absent; longitudinal series 26 32; operculum covered with cycloid scales, cheeks with few or no scales; top of head scaled to behind eyes, predorsal scales 7–10, usually with large scale close behind eyes; pectoral fin bases and area before ventral fins scaled. Two dorsal fins, first low with rounded margin, originating above and just behind ventral fin insertions; second dorsal origin just behind first dorsal fin; anal fin origin below and just behind second dorsal origin. Caudal fin with rounded margin. Pectoral fins large, with rounded margin. Ventral fins fused to form cup shaped disc, originating below pectoral fin insertions.
Size	To around 6 cm.
Colour	Pale brown to grey, paler below; scales on body and top of head often outlined in darker brown; head often with bars radiating from lower part of eyes; broad brown stripe above upper lip; body with four or five brown blotches along back; midsides with 5-6 irregularly shaped blotches; rear of caudal peduncle with enlarged brown spot, often with spot above and behind and similar spot behind and below on caudal fin base; body sometimes with faint brown spots forming irregular longitudinal lines. First dorsal fin with 2-3 grey oblique bars, and black or blue spot near base and end of fin; second dorsal fin with small spots forming oblique rows ventrally on fin; anal fin grey to clear, often with blue outer margin; caudal fin with spots forming wavy vertical bands on upper two thirds of fin; lower third of fin grey; pectoral and ventral fins grey to clear.
Feeding	Feeds mostly on crustaceans, such as amphipods and ostracods, and on mollusc siphons.
Biology	Oviparous, benthic spawners during spring in the upper reaches of estuaries with plentiful vegetation and salinity of less than 30%.
Remarks	The distribution of this species overlaps with that of Pseudogobius eos, and the central area of overlap in the two taxa (Murray Mouth to Glenelg River inclusive and north-west Tasmania) represents a hybrid zone between the taxa.
Similar Species	Differs from the similar Pseudogobius eos in having higher second dorsal and anal fin ray counts (I,8-9, usually I,8 second dorsal rays and I,7–9, usually I,8 anal rays versus second dorsal and anal rays I,6-8, usually I, 7 in P. eos), higher TRB (usually 10 versus usually 8), more lateral scales (27–30 versus 25–27), more predorsal scales (usually 10 versus usually 7–8), and is more robust compared to the more elongate P. eos with a typically larger head in males (mean 27.8 versus 25.5% SL).
Etymology	The specific name olorum is from the Latin olor (= swan), in reference to the Swan River, the type locality
Species Citation	Gobius olorum Sauvage 1880, Bull. Soc. Philomath. Paris (7)4: 43. Type locality: Swan River, Western Australia.
Author	Bray, D.J. & Gomon, M.F. 2022
Resources	Atlas of Living Australia Australian Faunal Directory Catalog of Fishes

Bluespot Goby, Pseudogobius olorum (Sauvage 1880)

References

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Larson, H.K. & Hammer, M.P. 2021. A revision of the gobiid fish genus Pseudogobius (Teleostei, Gobiidae, Tridentigerinae), with description of seven new species from Australia and South-east Asia. Zootaxa 4961(1), https://doi.org/10.11646/zootaxa.4961.1.1

McCulloch, A.R. & Waite, E.R. 1918. Some new and little known fishes from South Australia. Records of the South Australian Museum 1(1): 39-78 figs 26-31 pls 2-7 (described as Mugilogobius galwayi, type locality Patawalunga Creek, near Adelaide, South Australia) See ref at BHL

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Morgan, D.L., Thorburn, D.C. & Gill, H.S. 2003. Salinization of southwestern Western Australian rivers and the implications for the inland fish fauna - the Blackwood River, a case study. Pacific Conservation Biology 9(3): 161-171. https://doi.org/10.1071/PC 030161

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Sauvage, H.E. 1880. Description des gobioides nouveaux ou peu connus de la collection du Muséum d'Histoire Naturelle. Bulletin de la Société Philomathique de Paris 7 4: 40-58. See ref at BHL

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Whitley, G.P. 1933. Studies in Ichthyology No. 7. Records of the Australian Museum 19(1): 60-112 figs 1-4 pls 11-15 https://doi.org/10.3853/j.0067-1975.19.1933.691 [as Ellogobius (Lizagobius) galwayi]