western blue groper
The western blue groper (Achoerodus gouldii) is a slow growing and inquisitive fish that lives in the coastal reefs all along the Great Southern Reef and can live for up to 70 years. A large bony fish, they can grow to be up to 1.7 metres in length, and are not fully grown until they are about 30 years old. Even though they are called a ‘groper’ they are actually a large wrasse.
![blue groper ]4edit.jpg](https://images.squarespace-cdn.com/content/v1/5b60f1dcf2e6b1ee04e07deb/1598058114374-CPS7F6ILVJMB7AT3KBOK/blue+groper+%5D4edit.jpg)
Female first
These gropers are what is known as a protogynous hermaphrodite, meaning the entire species begins life as a female and some, but not all, change sex to males later in life. Females reach sexual maturity at about 15 years, but the change from female to male can take up to 35 years. This change usually occurs when they reach around 82cm in length and their colour changes from green to blue.
A male is made
Blue groper typically live in small groups, called “harems”, of one male, two females and many juveniles with the male being the largest in size and a bright cobalt colour, while the females maintain a greener hue. Interestingly, if the male is removed from the group, by either fishing or old age for example, then the harem’s dominant female takes the former male’s place – by changing in both sex and colour. This change begins within hours of the disappearance of the previous male!
Kings of the reef
Considered a keystone species, western blue gropers are an important part of the marine ecosystem. They have a critical role in maintaining the structure of their ecological community, and feed on species that have the potential to leave an ecosystem barren if left unchecked – like sea urchins for example. They have strong peg-like teeth that are perfect for pulling off reef organisms like abalone, other molluscs and crustaceans.
Curious creatures
Because of their size, the western blue groper has very few natural predators themselves, apart from large sharks and humans. They are a curious species, which is a delight for scuba divers, but it can also be a detriment as they make easy targets for spearfishers. Because they grow slowly, the species is vulnerable to overfishing.
Fast Facts:
Species: Achoerodus gouldii
Family: Labridae (wrasse)
Order: Labriformes (ray-finned fishes)
Feeding: Sea urchins, small crustaceans, abalone and other molluscs
Habitat: High profile rocky reefs
Distribution: Endemic to the GSR
Special Power: Suction feeding and reef maintenance
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