A north Queensland fisherman says the decision to dump dredge spoil from the Abbot Point coal terminal in the Great Barrier Marine Park will seriously damage the local fishing industry.

Three million cubic metres of spoil must be dredged as part of the expansion of the major coal terminal at Bowen, North Queensland.

The expansion was approved by Federal Environment Minister Greg Hunt, in December.

The Great Barrier Reef Marine Park Authority (GBRMPA) has now approved a proposal to dump the spoil in the Park, 25 kilometres offshore.

Bowen fisherman Nathan Rynn says he has grave concerns about the approval, and its impact on the fisheries.

"We're the eyes of the ocean, we're out there every day," he said.

"We don't have science degrees, us commercial fishers, but we know from our parents and grandparents who have passed this knowledge on for 100 years.

"We know what will happen after these sorts of events.

"We've seen the effects of Gladstone. There was chance that this didn't have to happen."

GBRMPA says there will be 47 conditions imposed on the dumping of spoil, which will minimise the impact on the environment.

But Mr Rynn says he finds no comfort in those measures.

"Once it's in the ocean, there's no controlling it," he said.