About Scorpaena jacksoniensis Steindachner, 1866
Scorpaena jacksoniensis has 12 spines and 9 soft rays in its dorsal fin, with the 4th spine being the longest, occasionally the 3rd. Its pectoral fin has between 16 and 18 fin rays, normally 17. The base of the pelvic fin is covered by embedded cycloid scales; these scales are also found on the rear of the species' thick-skinned underside. The lateral lacrimal spine has 2 points, occasionally 3. The forward lacrimal spine has 1 or 2 small spiny points on its rear edge. The rear lacrimal spine has a single point: in juveniles and young fish with a standard length of less than 100 mm (3.9 in), it is directed forwards and downwards, while in adults it points either straight down or diagonally rearwards. There is a spine-free ridge running through the middle of the interorbital space, an occipital pit, and a supplementary spine on the preoperculum. The pterotic spine is normally simple in young fish, but in large adults with a standard length greater than 28 cm (11 in), it may have 2 or more points. The gap between the upper and lower opercular spines is covered in thick skin that contains sensory pores and canals. There are many skin flaps and tentacles on the front part of the upper body. This species is frequently bright red in colour, but its overall colouration is extremely variable, ranging from light grey to bright red and marked with blotches. Small dark spots are normally present on the chest. Juveniles may have a white to purplish blotch across the nape. Males have a large black spot on the soft-rayed portion of the dorsal fin. The maximum recorded total length of this species is 40 cm (16 in).
Scorpaena jacksoniensis is endemic to the temperate seas of southeastern Australia. Confirmed occurrences range from as far north as Caloundra in Queensland, south to Beware Reef in Victoria. It may also occur as far west as Western Port, Victoria, but Victorian records are based on a small number of old specimens, and the species' confirmed southern limit is Jervis Bay in New South Wales. This species can be found in shallow estuaries, on rocky coastal reefs, and on deep offshore reefs. It is a benthic species that camouflages itself among rocks, corals and algae, and occurs at depths between 1 and 73 m (3 ft 3 in to 239 ft 6 in).
