Blue Groper

Blue gropers are two fish species from the genus Achoerodus. They are found in the coastal waters of southern Australia and distinguished by the bright blue colouring of the adult males. The eastern blue groper (Achoerodus viridis) is found from Hervey Bay in southern Queensland to Wilsons Promontory in Victoria. The range of the western blue groper (Achoerodus gouldii) stretches from the Houtman Abrolhos in Western Australia to west of Melbourne. Despite their name, they are not groupers, but wrasses (family Labridae).

The thick bodied blue gropers have peg teeth, heavy scales, a large tail and thick lips. Juveniles are brown to green brown. Adult females are brown to reddish-brown. Each scale may have a darker red spot. The adult males have the bright blue colouring that give the fish their name. The blue can range from deep navy to cobalt blue, and there may also be darker or yellow-orange spots or lines around the eyes.

All blue gropers begin their life as females. As they mature, they go through an initial phase, in which they may be male or female, before developing their adult colouring and reaching the terminal phase. Eastern blue gropers have been known to grow to 1.2 m (3.9 ft) in length and weights of 22 kg (49 lb), although fish over 15 kg are rare. The western species is larger, reaching 1.6 m (5.2 ft) and 40 kg (88 lb).

The fish live in a variety of coastal waters, especially exposed reefs. The western blue groper lives in water 5–65 m (16–213 ft), and the eastern species from the shallows up to 40 m (130 ft). They feed on invertebrates such as sea urchins, crabs and mussels. For the eastern species, spawning occurs from July until October, in estuarine seagrass beds, where the juveniles are usually found.

In 1998, the eastern blue groper was made the state fish emblem of New South Wales.