A scientific panel's investigation in to what caused the fish to develop bulging red eyes and severe skin lesions last year in Gladstone Harbour, forcing a three week fishing ban, has failed to deliver any answers.

The report by the Gladstone Fish Health Scientific Advisory Panel was commissioned last year after large numbers of the sick fish –mainly barramundi – were caught in the harbour and later found to have high parasitic levels.

Commercial fisherman Gary Grant, pictured on his boat in Gladstone Marina, is among the many who fear for the health of Gladstone Harbour. Credit:Gladstone Observer

Fishers in the harbour blamed the water quality, saying dredging had stirred up chemicals in the water, but the government denied the claims, instead pointing to the January floods as a more likely factor.

The report was inconclusive in determining a cause for the high parasitic levels, but it found the water quality was not a risk. It noted the fish were likely "stressed", although it did not offer a cause.