Mulloway are also known as jewfish, kob, soapie and croaker. Their
current scientific name is Argyrosomus
japonicus, although past names may include Argyrosomus hololepidotus and Johnius antarctica.
Mulloway are a fast growing, top-level estuarine
finfish. Growth rates of 2 – 3 year old fish exceed 1 mm per day, however
yearly increase in weight is greatest for 1 – 3 year old fish. Rapid growth of
mulloway is sustained until around 80 cm, when more energy is put into
reproduction rather than weight gain. This coincides with a length-of-maturity
for mulloway of 70 – 90 cm (this is a L50
value, which represents the length at which 50% of the size class is sexually
mature). Data suggest that mulloway spawn at the mouths of estuaries during
early summer, and juveniles migrate upriver into deep holes where they remain
until they are about 2 years old. At this time, these smaller fish commonly
remain in the estuaries, though during winter they may be found in greater numbers
on nearshore reefs where the water is warmer.
Mulloway can grow to phenomenal sizes. The
largest on record in Australia is 43 kg, however the largest on record in South Africa is 75 kg (if you wish to dispute these values,
please email mulloway@unsw.edu.au).
These largest fish may be greater than 30 years old.
Mulloway are highly prized by both anglers and professional fishers
alike. Whilst commercial fishing pressure Australia
wide is usually around 500 t per year, the recent National Recreational and
Indigenous Fishing Survey (Herny & Lyle, 2001) showed that the recreational
mulloway catch was as high as 975 t in 2000/01.
Recreational fishers generally develop methods to catch mulloway
through patience and cumulative experience. Most fishers develop their own unique
rigs, depending on the bait they are using and the locations at which they are
fishing. Although I cannot reveal the methods of individual fishers, common
baits used include live yellowtail, fresh tailor, squid or worms (off the beach).
Fishing effort should generally be concentrated in the lead up too the high
tide, going onto dusk. Information obtained through acoustic tracking indicates
that moon phase does not affect the movement of the mulloway,
however it may affect the activity of their prey. If you wish to catch a
mulloway, the best thing to do is to get out there with someone who is willing
to show you (contacts can be made at web forums such as www.fishraider.com.au). In the case of
catching this elusive sportfish, patience begets success – be prepared to spend
some time waiting for a hit (BBQ and beer help the time pass easier)!
