Western Blue Groper - bring the BIG boys back!

The Western Blue Groper, Achoerodus gouldii, is a benthic carnivore and feeds on sea urchins, crustaceans, mussels and small fishes. It lives in small groups on offshore rocky reefs, in depths ranging from 5 to 65 metres. The population stretches from Houtman Abrolhos in Western Australia, through South Australia to Port Philip Bay in Victoria.  

A school of juvenile Western Blue Groper. Photo: Grant Hobson

Sex!

The Western Blue Groper is a protogynous hermaphrodite. This means all juveniles are females and mature as green-coloured females at 15-20 years old, before developing their adult male blue colouring at 30 years old.  Western Blue Gropers can live up to an amazing 70 years, reach 1.6 meters in length and may weight up to 40 kg – now that’s a big, old fish!  Even specimens of 70-90cm can range in age from 22 to 45 years.

Over-exploitation

In an 'urchin shell', the Western Blue Groper is a long-lived, slow-growing, late-maturing, site-associated, nearshore reef fish species that has a strong population structure and changes sex with age – making it is highly vulnerable to over-exploitation. Considering their longevity and their diet, they may be a ‘keystone’ species in temperate reef ecosystems by controlling the abundance of other species.  Western Blue Groper is also fished commercially and recreationally and overfishing is the major threat to Western Blue Groper.  

Protection

For at least 30 years, the Western Blue Groper has been nominated (but not listed) for complete protection in S.A. In 2002, S.A. scientists suggested that no-take fishing areas would provide the most effective protection for the Western Blue Groper - adequate sanctuary zones within the new marine parks would make this level of protection a reality.