Northern Saratoga, Scleropages jardinii (Saville-Kent 1892)

Patchily distributed throughout most of the Gulf of Carpentaria drainage system, west to the Adelaide River, and throughout northern Queensland. Three separate populations occur: (1) in the Adelaide River to the Roper River, including Melville Island and Groote Eylandt, Northern Territory, and a translocated population in Girraween Lagoon, near Darwin; (2) Nicholson River system, Northern Territory; (3) CApe York, Queensland, from the Staaten River northward including most westerly flowing rivers of Cape York, and Harmer Creek and the Olive River systems within the Olive-Pascoe basin, eastern Cape York. Also occurs in the Trans-Fly system, southern Papua New Guinea.

Prefers clear low gradient streams, and pools and billabongs of floodplain wetlands, with abundant aquatic plant cover.

Dorsal fin 20-24; Anal fin 28-32; Lateral line scales 34-36.
Body elongate, compressed; depth moderate, greatest body depth 3.6-4.0 in SL; mouth large, upturned; forehead profile convex; head length more than one quater SL; snout 4.5-4.7 in SL; rear edge of jaw extending well beyond eye.
Head scaleless; large thick bony scales with canals form a mosaic-like pattern.
Dorsal fin placed posteriorly; anal fin below dorsal; pectoral fins pointed, not reaching pelvic bases, 3.5-4.1 in SL; pelvic fins 10-11 in SL.

Maximum TL 100 cm, commonly to 55 cm.

Dark brown to greenish dorsally, lighter brown to grey-green on sides with a silvery sheen; reddish crescent-shaped marking on most scales; dorsal, anal and caudal fins are dark brown to grey and speckled with small red spots; pectoral and pelvic fins dusky.

Opportunistic carnivore feeding on aquatic and terrestrial insects, small fishes and crustaceans.

Spawning generally occurs from September to early November when daytime surface temperatures approach 30°C. Females brood clutches of 50-200 eggs in the oral cavity.

Larvae hatch at 1-2 weeks and remain in the mouth for another 4-5 weeks. The young first feed at 2-3cm TL on micro-crustaceans, and become independent of the mother at 3.5-4cm TL

Renowned angling fish prized for its fighting ability and eating quality. The species may be susceptible to overfishing in localised stretches of rivers and billabongs.

Although popular, Northern Saratoga are territorial and aggressive fishes that are not suitable for community aquaria. The species has been successfully bred in captivity.

Evolved entirely from freshwater ancestor. Generally solitary; territorial.

Scleropages leichardti reportedly differs in fin ray counts, the angle of the mouth, reach of rear edge of the jaws, and chin barbels are present in all sizes of S. jardinii but only in S. leichardti over 15 cm. However, Pusey et al.(2016) consider S. jardinii to be a possible synonym of S. leichardti.

Osteoglossum jardinii Saville-Kent 1892, Proc. R. Soc. Qld. 8: 105. Type locality: Wenlock River, Queensland (as Batavia River) and Gregory River, Cape York, Gulf of Carpentaria, Queensland.

Gomon, M.F. & Bray, D.J. 2018

Australian Faunal Directory