The Tasmanian delicacies should have brought him about $200 at market; instead, he will pay close to $100,000 for the three lobsters.

Hansen was this week censured by a Federal Court judge in Canberra for setting his lobster traps in part of the South-east Commonwealth Marine Reserves Network – a huge collection of protected marine areas that stretches from Tasmania in the south to South Australia, Victoria and New South Wales.

On April 6, 2014, a marine surveillance aircraft photographed Hansen's fishing boat, Breakwater Bay, in marine national park waters off Hobart. Alarmed at being seen, Hansen "zoomed" out of the protective zone, killed a couple of hours and then returned to collect the pots, the court heard. He was questioned by police later that day.

Determined to send a message to other small-time fishermen, the federal government pursued Hansen, of Tasmania, through the courts in a two-year case that has racked up tens of thousands of dollars in legal costs.

Justice Robert Bromwich said he was going easy on the struggling fisherman – whose business is operating at a loss – by imposing a "somewhat lenient" $28,000 fine.

After he pays the legal costs of the federal Environment Department and his own lawyers, Hansen will be liable for close to $100,000.

The costs of Hansen's actions could not be seen as merely financial, Justice Bromwich said.

"Sustained commercial fishing, even through the use of only a few pots at a time, can destroy rock lobster populations in marine protected areas," he said.

Other impacts included physical damage to the sea bed from fishing gear being dragged by currents, and flow-on effects to the broader ecosystem from large rock lobsters being removed.

"None of these collateral detriments can be quantified, let alone attributed to this particular episode of illegal fishing," Justice Bromwich said. "But they strongly inform the need for general deterrence."

The maximum civil penalty fine for a breach of the Environment Protection Act is $90,000, Justice Bromwich said, and Hansen was lucky he hadn't been hit with criminal charges as well.

John Sansom, chief executive of the Tasmanian Rock Lobster Fishermen's Association, said that while he couldn't comment on the case, the association took a dim view of people taking lobsters from protected areas.

"We support the sustainability of the fisheries and the integrity of the rules, and we do frown on it when people break the rules," he said.

Hansen did not respond to a request for comment.