With the lobster season in full swing on the NSW South Coast, suspect fishers and their customers are being warned that Facebook is no easy black market for their illegal catch.
And buyers are being told to avoid unapproved vendors who offer sought-after marine species on social media - fisheries officers are online.
It comes after a man was found selling rock lobsters at a South Coast boat ramp for cash - undersized, and well in excess of the bag limit of two per person per day.
Facebook users in the Fairfield area of Sydney have been using the site to trade in fish way in excess of catch limits.
And late last month, a Towradgi man was busted in a pre-dawn sting at the breakwall near Wollongong Harbour, allegedly in possession of 17 crayfish.
This was just the tip of the iceberg, a well-informed source close to the industry told the Mercury.
"There's tons of poaching going on here," he said.
"The Illawarra's always been big for it."
The source said many of those involved in illegal lobster fishing are amateurs who catch a dozen or more then sell them on to acquaintances.
The NSW Department of Primary Industries describes its Statewide Operations and Investigations Group as a "crack squad" targeting illegal fishing along the coast.
DPI director of fisheries compliance Patrick Tully said the Batemans Bay perpetrator was a 48-year-old man from Bruce in the ACT, who had been under surveillance. He was allegedly observed exchanging fish for cash at Hanging Rock boat ramp, near the Catalina Country Club.
"Any person convicted of such an offence could face a maximum penalty of $110,000 for taking fish for sale when not the holder of a commercial fishing licence," Mr Tully said.
Another recent incident near Batemans Bay confirmed the "amateur salesman" theory.
Fisheries officers caught a 37-year-old local man with 11 eastern rock lobsters after diving at Garden Bay in Malua Bay.
"The daily bag limit and possession limit for Eastern Rock Lobster is two; these limits are to stop unlicensed fishers from accumulating large quantities of these high value species so they don't end up on the black market and threaten the livelihood of licensed operators," Mr Tully said.
DPI Fisheries also monitors illegal seafood sales of fish on social media.
"While many legitimate seafood businesses use social media to market their products, consumers should make sure they don't buy fish from illegal, backyard operators, who are easy to spot," Mr Tully said.