An investigation is under way on the NSW north coast after a critically endangered grey nurse shark washed ashore with its fins slashed off.
Fisheries officers have searched boats and buildings and interviewed fishermen since the mutilated and dying shark was found on a beach near Evans Head last week.
The grey nurse, a rare young breeding female, had both dorsal fins removed. Only about 1000 to 1500 grey nurse sharks survive off eastern Australia.
"It is illegal to remove the fins from any shark at sea," a spokesman for the Department of Primary Industries said.
"Penalties of up to $220,000 or 12 months' imprisonment can be applied."
Shark fin soup is considered a delicacy in some restaurants.
A Greens MP, Cate Faehrmann, said the mutilation showed a need for strengthened grey nurse protection.
"The loss of a breeding female from the tiny grey nurse shark population on the east coast of Australia is a huge blow to the desperate conservation effort to save this species," she said.
"The shark was still alive when it was found on the beach and suffered a slow, cruel death."
Ms Faehrmann called on the Minister for Primary Industries, Katrina Hodgkinson, to rule out fishing in grey nurse breeding areas.
"On taking office, she revoked protections for the grey nurse shark at South West Rocks and Solitary Islands to appease the fishing lobby," Ms Faehrmann said.
"She has since undertaken a lengthy public consultation process on grey nurse shark protection during which the public told her that they overwhelmingly support protective measures. Yet she still holds off on giving these sharks' habitat full protection."
The department's spokesman said a decision on the habitat protection would be delivered soon.
"The information collected through the department's public consultation process is in the final stages of analysis," he said.
The department said fisheries officers had issued about 3900 cautions and 2700 penalty notices in 2011-12. This led to 230 successful prosecutions for fishing offences, 105 court-imposed fines, 43 bonds, 14 community service orders and three jail sentences.
The department's policing work also led to about 24,000 fish being seized, along with 4800 items of fishing gear, including boats, cars, nets, rods and traps.