Dredging on Gladstone harbour.
Dredging on Gladstone harbour. David Sparkes

Newly released report blames dredging for harbour woes

QUEENSLAND'S seafood industry says serious questions have been left unanswered by a water quality report, released last week, which blamed highly turbid water on dredging activities in Gladstone harbour.

The WBDDO Water Quality: September and October 2011 report found that highly turbid waters during September and October 2011 occurred as a result of holes in the bund wall and dredge-related operations.

It also found several potential harmful algal species, which had previously been associated with fish kills, although the findings showed the algae was present before the Al Mahaar dredge began.

Gladstone fishers feel vindicated by report

The Queensland Seafood Industry Association has questioned the timing and non-release of reports that it says would have changed the outcome of the Independent Review of the Port of Gladstone.

The QSIA responded to the report on fish and human health problems through a submission published in its latest industry magazine.

The report said it considered the high levels of heavy metals found in turtles in the area difficult to interpret, as there was no baseline for comparison.

The QSIA has questioned what baseline study supported the review's statement that it "was likely that the floods and the over-crowding were the predominant cause".

The QSIA says research suggests otherwise, with cases in the Burdekin River where large numbers of barramundi flooded over the dam wall into the lower reaches, causing overcrowding.

"No such disease had been seen in these fish previously," the QSIA said.

"Likewise, when a breakdown of fish cages, releasing huge numbers of barramundi, occurred in severe weather events at Bathurst Island, no such disease outbreak was seen in these populations either."

A response from the Gladstone Ports Corporation said the report was specially commissioned after higher turbidity readings were recorded due to extreme tidal movements, high winds and the porosity of the bund wall.

GPC said the report concluded that "despite the highly turbid waters which for the most part exceeded AWQG (Australian Water Quality Guidelines), physicochemical, nutrients and contaminant concentrations measured during October 2011 were similar to and within ranges of concentrations previously recorded in Port Curtis, and also generally within acceptable guidelines".

GPC has previously acknowledged that dredging contributes to increases in turbidity but says many independent reports have found that dredging in Gladstone harbour is not responsible for sickness in fish or the release of heavy metals in the water.

Ports corporation points to seagrass recovery since the floods

THE Gladstone Ports Corporation says it has always acknowledged that dredging contributes to localised increases in turbidity.

Despite the increases, it says many independent reports have found that dredging in Gladstone harbour was not responsible for fish deaths or heavy metals.

The GPC says it has published hundreds of reports on its website, as required by licence conditions.

A statement provided by the GPC responding to The Observer's questions said more reports were published when requested.

"Additionally, the impact of any increase in turbidity will first affect seagrass - hence the loss of seagrass in the 2010/2011 floods," GPC said.

"Scientific data indicates that seagrass continues to recover since those floods even though dredging was taking place.

"A recent independent study conducted by James Cook University found that Gladstone Harbour is one of the few locations along the developed Queensland coast where seagrasses have shown good recovery."

Gladstone Ports Corporation has advised The Observer the Western Basin Dredging Website was down on Monday morning but for anyone who wants a copy of the WBDDP water quality September and October 11 report they can email the GPC at communityrelations@gpcl.com.au.