|
|
|
West Australian Dhufish

West Australian Dhufish

Glaucosoma hebraicum

The West Australian Dhufish is endemic to southern Australia, occurring from Shark Bay through to the Recherche Archipelago. Adults often occur in deep water (to 120m depth); however they also congregate on reefs and rocky substrates during the spawning season from December to March. They are a slow growing and long living species, living to 40 years of age. Males grow faster and attain a larger size then females and sexual maturity is reached at 7 years (30 centimetres) for females and 6 years (32 centimetres) for males. The species grows to a maximum size of 1.22 metres.

West Australian dhufish are a robust deep-bodied fish with a large head eyes and mouth and are bright silvery to grey with a black line through the eye. Males are easily distinguished by the long filament on their dorsal fin, setting them apart from females. They are one of the most commercially valuable and recreationally sought after finfish in Western Australia. Their excellent eating qualities and large size makes them a popular fishing target. Increased fishing pressure has been powered by developments in technology particularly with echo sounders and GPS systems and has led to a decline in the abundance and size of dhufish, particularly in inshore waters.

West Australian dhufish are opportunistic predators and feed on a variety of prey, including octopus, cuttlefish, squid, moray eels, seahorses, crustaceans and fish such as wrasse and bullseyes.

Seasonal movements of West Australian dhufish have been observed in the Geographe Bay region. Males move into the bay during October and November, where they compete for social and spawning status. During this time they establish communal display areas known as ‘leks’. Females arrive in December, where large numbers aggregate for spawning, which occurs over a few months peaking in January and February. The larger females produce more eggs (up to three million eggs), better quality eggs and spawn more frequently. Fertilised eggs are then carried north by the Capes Current where they drift for approximately one week before hatching. It is this southern population that provides an important recruitment area for northern populations. The dhufish then move offshore in March. Seasonal migration occurs in winter also, however not for means of reproduction (as the male gonads are non-reproductive) but instead for feeding. There is thought to be a correlation with the movement of white crayfish at this time.

Other common names include: Dhufish, Jewfish, Jewie, Western Jewfish, Westralian Jewfish, Western Australian Jewfish

 

Occurrence at the Busselton Jetty:

Solitary juveniles (up to 30 centimetres) of the West Australian dhufish are spotted occasionally from the underwater observatory.

Image by: O. Rynvis