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| Common Name | |||
| estuary perch (estuarine perch) | |||
| Scientific Name | |||
| Macquaria colonorum (GYnther, 1863) | |||
| Conservations Status | |||
| Rare | |||
| Distribution and Abundance | |||
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| Essentially a fish of coastal drainages from the Murray mouth in SA to Northern NSW, Estuary perch is rare in the Basin, and recorded only from the Lower Murray, Lower Lakes (Alexandrina and Albert) and the Coorong. Specimens have been recorded in recent years from as far up the Murray as Swan Reach. | |||
| Identification | |||
| A medium sized fish with a deep, laterally compressed body. Maximum length 750 mm, maximum weight 10 kg; usually less than 1.5 kg. There is a single dorsal fin with a moderately deep notch between the spinous and soft-rayed portions. The pelvic fins are inserted behind the origin of the pectoral fins. The back is generally dark grey and silvery, paling to whitish on the lower sides. The tail is forked, the eye is moderately large and the mouth is of moderate size with a protruding lower jaw. The dorsal head profile is slightly concave. | |||
| Biology and Habitat | |||
| The Estuary perch predominantly lives in tidal or estuarine waters, but will penetrate significant distances upstream into fresh waters. It breeds in seawater at the entrance of estuaries in winter when water temperatures are from 14 to 19¡C. Males mature at 220 mm length and females at 280 mm. Fecundity is high and increases with fish length: a 34 cm fish has 182,000 eggs and a 40 cm fish 540,000. The eggs are 1.3-2.4 mm in diameter, round, non-adhesive and semi-buoyant. They hatch in 2-3 days and the newly hatched larvae are about 2.2 mm long. The species is an opportunistic carnivore, favouring mid-water prey such as shrimp and fish. The composition of the diet from freshwater environments in the Basin is unknown. However, a study of diet in both freshwater and estuarine habitats of the Hopkins River found that both large (> 250 mm) and small (< 250 mm) fish consumed mostly caddisfly larvae, and shrimp ( Paratya ) were the next most common item. In the estuary, large fish (> 300 mm) fed mainly on fish, amphipods and shrimp, in descending order of importance, whereas small fish (< 250 m) fed mainly on shrimp and then amphipods. The diet varied seasonally, with terrestrial insects becoming prominent in November. Apart from the adult migration downstream to estuaries to breed, little is known of movements. | |||
| Potential Threats | |||
Since the construction of the barrages and decline in river flows, the abundance of this species has fallen significantly in the Lower Lakes (Alexandrina and Albert). |
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| General References | |||
| Click here for complete list of references | |||
| Allen et al. 2002; | |||
| Harris & Rowland 1996; | |||
| Howell et al. 2004; | |||
| Koehn & O'Connor 1990; | |||
| McCarragher & McKenzie 1986; | |||
| Merrick & Schmida 1984; | |||
| Sim et al. 2000; Wedderburn & Hammer 2003. | |||
| Wedderburn & Hammer 2003. | |||
| PDF Links | |||
| To download these PDFs visit our on-line publications ordering system through these links. | |||
| Fish Factsheet - estuary perch (estuarine perch) | |||
| Fishes of the Murray-Darling Basin: An introductory Guide | |||