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Fish health

What are the concerns?

After the significant rainfall events in December 2010 and January 2011 (PDF, 1.1M)*, Gladstone Harbour experienced a number of abnormal occurrences associated with fish and other marine animal health.

In August 2011, the Queensland Government was made aware that some locally caught fish were presenting with symptoms such as cloudy eyes, skin discolouration and lesions. Some commercial fishers also reported concerns that human health illnesses were related to water quality.

On 16 September 2011, Fisheries Queensland temporarily closed Gladstone Harbour and surrounding waters to fishing, while the conditions were investigated.

Fisheries Queensland commenced monitoring fish health in Gladstone Harbour, based on a visual examination of fish. The initial monitoring looked at the distribution and severity of external symptoms of fish within the harbour. Samples were also provided to Biosecurity Queensland for further tests and investigations.

This information formed part of the bigger picture developed with information collected on water quality, human health and seafood quality.

The temporary closure was lifted on 7 October 2011 as Queensland Health found no evidence relating the conditions identified in fish and illness in humans.

What is being done?

In response to the fish health issues, the Queensland Government set up an investigation program which included fish and water quality sampling and testing and investigation into human health concerns.

Fisheries Queensland, part of the Department of Agriculture and Fisheries, continued to assess the health of fish in the Gladstone region, including fin fish, sharks and crustacean species. Samples of a wide range of fish, crustacean and mollusc species are provided to Biosecurity Queensland for more detailed studies.

The sampling program was expanded to record how seasonal variations and locations of fish compare scientifically between sites.

Fisheries Queensland monitored and collected fish from waterways including The Narrows, Graham Creek (Curtis Island), Calliope River, Boyne River, Hamilton Point and Rodds Bay, as well as within the Gladstone Harbour.

What are the results?

Biosecurity Queensland (part of Department of Agriculture and Fisheries) tests showed infestation of a parasitic flatworm (Neobenedenia sp) in barramundi, as well as a different type of parasitic flatworm on sharks, and common shell erosion on some crustaceans, but there was no common cause identified in other fish species tested.

The parasitic flatworm was not unexpected given the major flooding events in 2011.

This Gladstone Fish Health Scientific Advisory Panel supported ongoing investigation of the issue.

The panel was not able to provide conclusions on the cause of fish conditions observed in Gladstone Harbour, and recommended further monitoring and research. However, the panel did confirm that there is no risk to human health.

The government implemented the panel’s recommendations through an Integrated Aquatic Investigation Program for Gladstone Harbour.

For more fish health information about fish health sampling, reports and results, visit the DAF website.

For more food safety information on seafood products, visit Safe Food Queensland.

Fish health survey interim report June/July 2012

Fish sampling conducted in June and July found fish health in Gladstone waters continuing to improve.

A survey report released by Fisheries Queensland found fish to be in overall good health within Gladstone, including the harbour and spoil grounds.

The most significant finding was evidence of fish healing from previous injuries, pointing to fish resilience and indicating that they were overcoming their previous ill health.

Read the Fish Health Survey Interim Report June/July 2012 (PDF)*.

Gladstone Harbour Fish Health Investigation 2011-2012

The 12-month fish health investigation found that Gladstone Harbour and adjacent waterways were stressed by flooding and fish entering from Lake Awoonga. Dredging and associated turbidity may have put additional stress on the ecosystem, but it was not the primary cause.

In 2012 fish health in Gladstone Harbour had returned to a more normal situation and fish were recovering from previous ill health.

The only differing factor in 2011 was significant rainfall, subsequent flooding and the significant number of fish introduced from Lake Awoonga. Flooding also occurred in 2012 and 2013 but sick fish have not been reported.

Read more about the findings of the fish health investigation.

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Last updated
31 July 2013