Retropinna semoni
FAMILY
Retropinnidae
TAXONOMY
Prototroctes semoni Weber, 1895, Burnett River, Queensland, Australia.
OTHER COMMON NAMES
German: Australischer Stint; Polish: Rakietniczka semona.
PHYSICAL CHARACTERISTICS
Total length 3.9 in (10 cm), small, elongate; dorsal fin posteriorly placed; adipose fin present. Scales absent on head. Olive green dorsally, golden to orange or purple laterally, silvery ventrally. Fins enlarged in breeding males. Has only a left gonad. Often smells of cucumber when fresh.
DISTRIBUTION
Widespread in coastal drainages of southeastern Australia, from the Fitzroy River in southern Queensland to eastern South Australia; also in the Cooper Creek drainage of Lake Eyre.
HABITAT
Slow-flowing streams and rivers, lakes, and ponds/pools; also in brackish habitats. Schools among riparian vegetation and open waters at all depths.
BEHAVIOR
Gregarious, forms large schools from midwater to the surface in large open waters.
FEEDING ECOLOGY AND DIET
Feeds on insects, microcrustaceans, and algae. An important component of the diets of other fishes.
REPRODUCTIVE BIOLOGY
Sexual maturity usually attained at end of first year at about 2–3.9 in (5–10 cm). Some fish from inland and northern drainages may reach maturity in 9–11 months and at less than 1.6 in (4 cm). Spawns in fresh waters during spring. Spawning individuals develop nuptial tubercles on scales and fin rays. Releases 100–1,000 adhesive eggs (0.03 in/0.08 cm) over the streambed and/or aquatic vegetation. Larvae of about 0.18 in (0.45 cm) hatch after 10 days. Coastal populations may be amphidromous.
CONSERVATION STATUS
Not listed by the IUCN.
SIGNIFICANCE TO HUMANS
Introduced to Tasmania as forage for introduced trouts.
