Girella elevata
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| Girella elevata | |
|---|---|
| FMIB 36163 Girella elevata, Macleay | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Centrarchiformes |
| Family: | Girellidae |
| Genus: | Girella |
| Species: | G. elevata |
| Binomial name | |
| Girella elevata W. J. Macleay, 1881 | |

Girella elevata, the rock blackfish, Eastern rock blackfish, black rockfish or Eastern rock blackfish drummer is a species of marine ray-finned fish, a sea chub from the family Kyphosidae. It is found in the southwestern Pacific Ocean around eastern Australia and northern New Zealand.
Girella elevata has a moderately deep, compressed oval shaped body with a narrow caudal peduncle and a small head which has a slightly bulging forehead. It has a small mouth which does not extend as far as the eye. Each jaw is equipped with a two rows of teeth, an outer row of flattened three-crowned teeth which do not overlap and an inner row of similar but much smaller teeth. It has ctenoid scales which cover much of the body and it has a continuous lateral line which is arched in parallel with the body's dorsal profile. The dorsal fin is continuous and there is almost no difference in form between the spiny and rayed parts of the dorsal fin. The spiny part is about a third longer than the rayed portion. The spines become longer towards the trail and the soft rays are noticeably longer than the spines. The soft-rayed part of the dorsal fin is rounded. The anal fin is similar in shape to and lies opposite to the soft-rayed part of the dorsal fin. It has a very large and deeply forked caudal fin It has small pectoral fins in which the upper rays are the longest and small pelvic fins, located below, and just to the rear of the base of the pectoral fins.[1] The dorsal fin has 14-16 spines and 11-12 soft rays while the anal fin has three spines and 11-12 soft rays. It can reach a length of 62 centimetres (24 in) standard length[2] and average weight of 1 kilogram (2.2 lb) standard weight to 2 kilograms (4.4 lb) standard weight, but can exceed 3 kilograms (6.6 lb).[3] This species is uniformly blackish-brown to grey on their body[4] with a black margin along the posterior edge of the operculum. The juveniles are less uniformly coloured, being more mottled, as the dark colour is broken by bands on the back.[1] It can be confused with the silver drummer (Kyphosus sydneyanus).[4]
Distribution
Girella elevata is found in the south-western Pacific Ocean in coastal eastern Australia and northern New Zealand. In Australia it occurs from Noosa Heads, Queensland south to Apollo Bay in Victoria and northern Tasmania, although it is rare west of Wilsons Promontory in Victoria. It is also found around Lord Howe Island in the Tasman Sea.[1]
Rock blackfish have been reported in waters off Japan, although these were most likely Girella leonina or punctata, both having “blackfish” as part of their Japanese names (both of which are primary targets of Japanese ISO fishers, who sometimes charter helicopters for day trips to offshore islands to fish for them[5]). Another related species that can be mistaken for elata is the dusky sea chub, Girella freminvillii, which has been seen in the Galápagos Islands.[6]
Habitat and biology
Girella elevata show a preference as adults for areas of rocky reef in exposed situations where they can be found from the surf zone down to around 25 metres (82 ft). They are frequently observed by divers in caves or below ledges. The juveniles occur in rockpools, estuaries and areas of rocky reef in shallow waters.[7] This species may live as long as 45 years.[8] It is omnivorous and feeds on a range of invertebrates and algae.[4]