Teleostei (teleosts) >
Galaxiiformes (Southern smelts) >
Galaxiidae (Galaxiids) > Galaxiinae
Etymology: Galaxias: Greek, galaxias, ou = a kind of fish (Ref. 45335).
More on author: Castelnau.
Issue
The high level of genetic divergence between most of the populations in South Africa suggests that it may represent a species complex rather than a single species (Ref. 32965, 93589). There is an urgent need for detailed morphological diagnostic studies, and the determination of the ecological requirements and conservation status of each of the cryptic forms of this species (Ref. 93589).
Environment: milieu / climate zone / depth range / distribution range
Ecology
Freshwater; benthopelagic. Subtropical; 18°C - 24°C (Ref. 12468); 30°S - 34°S
Africa: endemic to South Africa, occurs in Cape coastal streams and rivers from the Krom and upper Gamtoos River systems (south coast) to the Clanwilliam Olifants system (west coast)(Ref. 32965, 52193, 93589, 93786).
Length at first maturity / Size / Weight / Age
Maturity: Lm 3.9, range 4 - 4 cm
Max length : 7.5 cm TL male/unsexed; (Ref. 52193)
Dorsal spines (total): 0; Dorsal soft rays (total): 9 - 13; Anal spines: 0; Anal soft rays: 9 - 14; Vertebrae: 36 - 42. Diagnosis: body slender and cylindrical, without scales; dorsal fin placed far back over anal fin; caudal fin truncated; mouth terminal, jaws with teeth; large eyes; internal organs visible in live specimens (Ref. 52193). Loss of two laterosensory pores beneath the lower jaw; elongate caudal peduncle (Ref. 93822).
Facultative air-breathing in the genus (Ref. 126274); May penetrate some distance inland and is widespread in lakes and rivers (Ref. 3563), which may be either acid (pH 5-6,5) or alkaline (pH 8-9) (Ref. 93592, 93822). Prefers gentle currents within shelter of banks near the head of pools (Ref. 3563, 52193). Small but extremely hardy, they are known to tolerate a wide range of water and temperature conditions (Ref. 5214, 6164, 52193, 93591, 93592). Feeds on small drifting invertebrates (Ref. 7248, 52193). Spawning period occurs in spring up to middle of summer (Ref. 5214, 33843, 52193), depending on the conditions (Ref. 52193). Ripe eggs are demersal, relatively large and numbering about 30-40 (Ref. 93592). Their small size and cryptic color enable them to avoid predators (Ref. 52193).
Breeding occurs in spring or summer depending on local conditions (Ref. 52193). Galaxias zebratus does not migrate to the sea for breeding purposes (Ref. 41543, 93592).
Skelton, P.H., 2001. A complete guide to the freshwater fishes of southern Africa. Cape Town (South Africa): Struik Publishers, 395 p. (Ref. 52193)
IUCN Red List Status (Ref. 130435)
Threat to humans
Harmless
Human uses
Fisheries: of no interest; aquarium: commercial
Tools
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Estimates based on models
Phylogenetic diversity index (Ref.
82804): PD
50 = 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00490 (0.00205 - 0.01170), b=3.12 (2.91 - 3.33), in cm total length, based on LWR estimates for this (Sub)family-body shape (Ref.
93245).
Trophic level (Ref.
69278): 3.5 ±0.37 se; based on food items.
Resilience (Ref.
120179): Low, minimum population doubling time 4.5 - 14 years (Fec<50).
Fishing Vulnerability (Ref.
59153): Low vulnerability (10 of 100).
