A 58cm King George whiting caught near Swan Island in Port Phillip Bay has been aged at 9 years old, born in the winter of 2007.
A King George whiting of this age is very unusual in Victorian waters.
Most fish of this size and age have already migrated to spawning grounds, thought to be off far western Victoria and into south-east South Australia.
The whiting weighed 1.3kg and was caught in November 2016 by Russell Shipley, who is a volunteer angler diarist helping fisheries scientists monitor fish stocks by recording his catch data and time spent fishing.
The Angler Diary Program is supported by recreational fishing licence fees.