A LARGE number of catfish are still gathered in the upper reaches of the Boyne River and not much can be done to stop them dying.
Gladstone Area Water Board (GAWB) chief executive Jim Grayson said GAWB's hatcheries expert had been monitoring the fish, which are in a section of the river downstream from Awoonga Dam.
GAWB is not responsible for the section of river where the catfish are gathered and it says the fish did not come from over the dam wall.
Instead, it is believed they swam upstream when large amounts of fresh water flowed down the river in February and March.
More than 100 dead catfish washed up at the Boyne River mouth last mouth and the cause of their death caused some concern in the community after a year of fish disease controversies.
The Department of Environment and Heritage Protection is investigating.