About Scorpis lineolata Kner, 1865
This species, commonly called the silver sweep, has the scientific name Scorpis lineolata Kner, 1865. The silver sweep has a deep, strongly compressed body with a thin caudal peduncle. Its head is moderately sized with an almost straight dorsal profile, a short snout, and quite large eyes. The small, oblique mouth holds small but strong jaw teeth arranged in broad bands, where the outer band is enlarged and recurved. Most of the body is covered in very small ctenoid scales, and it has a gently curved lateral line. The dorsal fin is continuous, starting with a very short first spine; there are 10 total spines that progressively become taller towards the tail. The first rays in the soft-rayed section of the dorsal fin are only slightly taller than the spiny section, giving the dorsal fin an almost straight profile. The soft-rayed portion of the dorsal fin contains 26 to 28 soft rays, and this soft portion is notably longer than the spiny portion. The anal fin has 3 spines and 27 to 28 soft rays. Its pectoral fins are small, with the uppermost rays being the longest. The pelvic fins are also small, and are positioned below and behind the pectoral fins. Silver sweeps are greyish, blue-grey, or green-grey on their dorsal side, and silver-grey on their ventral side, with blackish coloring at the edge of the gill cover and the base of the pectoral fin. This species can grow to a maximum length of 30 cm, or 12 inches. The silver sweep is distributed in the southwestern Pacific Ocean off the coasts of Australia and New Zealand. In Australia, it occurs from Moreton Bay in Queensland south to Tasmania, and west as far as Victor Harbor, South Australia. It is also found in the Tasman Sea around Lord Howe Island and Norfolk Island. Silver sweeps are a common fish along Australia’s east coast, particularly in New South Wales. In New Zealand, this species is distributed around the entire coast of the North Island. Adult silver sweeps live on coastal reefs at depths down to at least 50 metres, or 160 feet. They feed on plankton above rocky reefs, where they form schools. Juveniles settle in tide pools and can also be found in the brackish waters of estuaries. Silver sweeps spawn during the winter, with a peak breeding season between May and August. Their eggs are pelagic. Young fish grow very quickly for their first 2 to 3 years, but growth slows significantly after they reach sexual maturity, and the species can live for over 50 years. Silver sweeps have separate sexes.
