The Illawarra has featured prominently in a statewide list of "hotspots" for illegal fishing activity.
Following a focus on prohibited size fish offences across NSW since March 2018, NSW Department of Primary Industries (DPI) Fisheries officers have seized 5379 illegally harvested fish and shellfish during a state-wide operation called 'Operation Small Fry'.
NSWDPI director of Fisheries Compliance Patrick Tully said 1350 offences were detected during the operation, with $102,500 worth of on-the-spot fines handed out to those caught possessing or selling prohibited size fish.
Twenty six others will, or already have faced the courts for serious offences involving prohibited size fish.
"There were 20 locations where NSWDPI fisheries officers found most offences occurring during the year-long operation," he said.
"Greater Sydney was the worst performer with five metropolitan postcodes in the top 10, including Pyrmont (number one, 63 offences), Kymeah (number six, 30 offences), Port Botany (number seven, 28 offences), Kurnell (number eight, 25 offences) and La Perouse (number nine, 22 offences).
"Regional areas in the top 10 offending locations were Port Kembla (number two, 60 offences), Woolgoolga (number three, 41 offences), Shellharbour (number four, 37 offences), Eden (number five, 34 offences) and Merimbula (number ten, 19 offences)."
The remaining hotspots making up the top 20 in order were: Swansea Heads, Banksmeadow, Mulwala, Picnic Point, The Entrance, Windang, Cronulla, Jervis Bay, Chipping Norton and Batemans Bay.
Men were the most prolific offenders by far, with 30-34 year olds being the most over-represented age group.
Mr Tully said whiting, snapper, bream, tarwhine and kingfish were the finfish species most commonly involved.
"In one instance, fisheries officers from North Sydney found and seized 41kg of prohibited size Yellowtail Kingfish concealed in a man's boat on Christmas Eve 2018," Mr Tully said.
"Turban snails, abalone, crabs and lobsters were the most common invertebrates seized by fisheries officers.
"DPI appreciates the wider community's help bringing these offenders to account with 652 reports about prohibited size fish coming through the Fishers Watch service.
"We've learnt a lot through Operation Small Fry and continuing to reduce the prevalence of prohibited size fish offences in NSW will remain an enduring priority for us. We'll be refocusing our efforts on these problem areas later in the year through another state-wide operation tentatively named Operation Bigger Fish."
Anyone spotting illegal fishing activity should report it to the Fishers Watch phone line on 1800 043 536.
People can also report online at www.dpi.nsw.gov.au/fishing/compliance.