Spangled Perch, Leiopotherapon unicolor (Günther 1859)
Spangled Perch, Leiopotherapon unicolor. Source: Gunther Schmida / http://www.guntherschmida.com.au. License: CC BY Attribution-Noncommercial-ShareAlike 3.0
Spangled Perch, Leiopotherapon unicolor (Günther 1859)
More Info
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Distribution |
Widely distributed through central Australia from the Murchison River, WA (27º54´S) to vicinity of Newcastle, NSW (32º56´S), and S to the Finke River drainage (25º33´S); this species has the largest distribution of any freshwater teraponid, occurring in major rivers, isolated drainages, and ponds throughout the northern two-thirds of Australia; resident in a variety of water conditions, from running to still and clear to nearly opaque with a wide salinity and temperature tolerance. |
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Features |
Meristic features: Dorsal fin XI-XIII, 9-12; Anal fin III, 7-10; Pectoral fin 15-16; Pelvic fin I, 5; Lateral line 45-57; Transverse scales 7-9/1/16-20; Gill rakers 5-6+1+10-12; Vertebrae 11+14. Body slender, depth 2.7-3.5 in SL, ovate variably compressed, more rotund in young. Dorsal profile more pronounced than ventral. Dorsal profile straight from snout to nape, then slightly convex to dorsal origin. Ventral profile evenly convex from lower jaw to anus. Head length 2.6-3.2 in SL; Snout elongate, length 2.9-3.9 in HL. Nostrils separated by a distance equal to one and one-half diameters of posterior nostril. Eye width 3.6-5.8 in HL. Inter-orbital region with ridges. Jaws equal, length 2.5-3.4 in HL; gape oblique; maxillary reaching to beyond vertical drawn through anterior edge of eye; teeth strong; conic; outer row enlarged; inner villiform, in bands; no teeth on vomer or palatines. Lacrimal with weak serrations. Preoperculum serrate; serrations largest on posterior edge. Lower opercular spine longer and stronger; not extending beyond edge of opercular lobe. cleithrum exposed; serrate along posterior edge; scales on side. Supracleithrum covered with scales for most of its length. Posttemporal not exposed; covered with skin and scales. Scales finely ctenoid; lateral line continuous, smoothly curved; 3-6 scales on caudal; scales above lateral line; scales below lateral line; 15-20 predorsal scales to occiput; one row of scales in sheath at base of dorsal, sheath extending to second dorsal ray; two rows of scales in sheath at base of anal fin, sheath extending to third anal ray; cheek scales in 6-9 rows. Dorsal fin continuous, base 2.0-2.4 in SL; spinous dorsal arched; first spine short; third or fourth longest, 2.8-3.5 in HL, those following decreasing in length to ultimate. Longest dorsal spines shorter than longest dorsal rays, longest dorsal ray 1.9-2.4 in HL, soft dorsal rounded. Anal spines short; second and third spines sub-equal, twice length of first, longest anal spine 3.0-4.1 in HL, shorter than longest anal ray, longest anal ray 2.1-2.5 in HL; soft anal rounded. Pectoral fin asymmetrically pointed; fourth ray longest. Ventral fins pointed; first ray longest; reaching one-half to two-thirds distance to anus. Caudal fin slightly emarginate. |
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Size |
To around 31 cm SL. |
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Colour |
Body greyish, darker above; each scale with darker edge; intensity of scale pigmentation decreasing ventrally, ventral scales with whitish centre. Head darker above, paler below; lips and upper surface of snout quite dark; cheek and opercle with randomly distributed small spots; lower lip slightly pigmented; larger specimens with spots on side of cleithrum. Spinous portion of dorsal fin uniformly dusky; soft portion brownish with paler margin. Spinous portion of anal fin white, soft portion dusky, especially anteriorly. Caudal fin dusky, especially lower lobe; white band on lower edge of ventral lobe. Pectoral and pelvic fins colourless. |
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Feeding |
Omnivore |
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Biology |
Spawning occurs at night during summer following a rise in water temperature associated with an increase in water depth. Fish in rivers migrate upstream and those in lakes or ponds move to the shallows to spawn on soft substrates. Eggs are demersal and randomly dispersed. Larvae hatch after 2 days and larval development is complete in around 24 days. |
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Remarks |
The southern limit of the distribution appears to be related to the species intolerance to water temperatures below 5.3°C, with the limit of distribution conforming well with the 4.4°C isotherm for the minimum average winter temperature. Spangled Perch are reported to aestivate when water bodies dry up and to tolerate high water temperatures (LD50, 39.0'C.); juveniles are known to migrate from permanent water courses during heavy rains when sheets of water cover country sides. |
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Etymology |
The name unicolor refers to the uniform coloration of the dried skins on which the original species description was based. |
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Species Citation |
Therapon unicolor Günther, 1859, Cat. fish. Brit. Mus. 1: 277. Type locality: Mosquito Creek, Gwydir River, NSW. |
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Author |
Dianne J. Bray & Vanessa J. Thompson |
Spangled Perch, Leiopotherapon unicolor (Günther 1859)
References
Allen, G.R. (1982). Inland Fishes of Western Australia. Perth : Western Australian Museum 86 pp. 6 figs 20 pls.
Allen, G.R., Midgley, S.H. & Allen, M. (2002). Field guide to the freshwater fishes of Australia. Perth : Western Australian Museum 394 pp.
Beumer, J.P. 1979. Reproductive cycles of two Australian freshwater fishes: the spangled perch, Therapon unicolor Gunther, 1859 and the East Queensland rainbowfish, Nematocentris splendida Peters, 1866. J. Fish Biol. 15: 111-134.
Bostock, B.M., Adams, M., Laurenson, L.J.B. & Austin, C.M. (2006). The molecular systematics of Leiopotherapon unicolor (Gunther, 1859): testing for cryptic speciation in Australia’s most widespread freshwater fish. Biological Journal of the Linnean Society 87: 537–552. DOI: 10.1111/j.1095-8312.2006.00587.x
Grant, E.M. (2002). Guide to Fishes. Redcliffe : E.M. Grant Pty. Limited 9th Edn 880 pp.
Günther, A. (1859).Catalogue of the acanthopterygian fishes in the collection of the British Museum. Gasterosteidae, Berycidae, Percidae, Aphredoderidae, Pristipomatidae, Mullidae, Sparidae. London : British Museum Vol. 1 524 pp.
Leggett, R. & Merrick, J.R. (1987). Australian Native Fishes for Aquariums. Artarmon : J.R. Merrick Publications 241 pp. 142 figs.
McDowall, R.M. (ed.) (1980). Freshwater Fishes of South-eastern Australia. Sydney : A.H. & A.W. Reed 208 pp. figs
Vari, R.P. (1978). The terapon perches (Percoidei, Terapontidae) a cladistic analysis and taxonomic revision. Bull. Amer. Mus. Nat. Hist. 159(5): 175–340 figs 1–94.
Wager, R. & Unmack, P.J. (2000). Fishes of the Lake eyre catchment of central Australia. Department of Primary Industries Queensland Fisheries Service 88 pp.
