April 4, 2022
Biosecurity Queensland is investigating a report that the invasive pest fish species tilapia has been spotted in Cooby Creek, north of Toowoomba.
A Biosecurity Qld spokesperson said Cooby Creek was a tributary that flows into the Murray Darling Basin. If confirmed, this would be the first-time tilapia have been found in this catchment.
Tilapia were introduced into Australia in the 1970s as ornamental fish and are now a major threat to Australia’s native biodiversity.
Photographs of the fish were provided to Biosecurity Queensland on March 24 but were inconclusive.
Biosecurity officers have conducted initial sampling in the area, but no tilapia have been found.
More extensive sampling will be undertaken, including environmental DNA sampling, but recent flooding has limited access.
It is expected further sampling will not be possible for the next week or two.
Studies have shown that around half of the Murray-Darling Basin is currently suitable habitat for tilapia, including parts of NSW, Victoria and South Australia.
It is expected that tilapia would have significant impacts on a range of native species, and lead to reduced water quality in this system if established.
The spokesperson said that in ponds and small dams, poisons can be used to completely remove pest fish but these were not effective for open waterways such as Cooby Creek.
There are currently no effective control methods for tilapia in open waterways.
Tilapia are now widespread on the east coast of Queensland. However, Biosecurity Queensland maintains a strict “no-take” approach to reduce the spread of this noxious fish. Tilapia are restricted matter under the Biosecurity Act 2014.
The spokesperson said most new infestations are caused by people moving live fish between catchments. This included private dam stocking and moving tilapia between catchments to use as bait or to create new “fisheries”.
“If you see something you think might be tilapia, take a photo and note the exact location, and call Biosecurity Queensland on 13-25-23 or report it online,” the spokesperson said.
“If you catch tilapia in the wild, humanely kill them and do not return them to the water.”
- For more information visit Business Queensland.
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Spotted Tilapia (Tilapia mariae)
- Ranges from dark olive-green to light yellow
- 8 or 9 dark bars or blotches on the sides (obvious in younger fish)
- Grows to 30cm
- Deep-bodied with a thin profile and long pointed fins
Mozambique Tilapia (Oreochromis mossambicus)
- Grows to more than 36cm
- Lives up to 13 years
- Usually dark grey or almost black but can be silver with 2-5 dark blotches/spots on the side
- Breeding males can have red tips on their fins
- Deep-bodied with a thin profile and long pointed fins
