The Environment Protection Authority (EPA) has continued to review environmental monitoring data following the release of its
Preliminary analysis of environmental samples for florfenicol in southern Tasmania in December 2025.
EPA Director, Catherine Murdoch, said that environmental monitoring for the first four marine farming leases being treated with florfenicol commenced on 5 November 2025 and continued into February, reflecting multiple treatment events at some sites.
The environmental monitoring has been undertaken in accordance with required Antibiotic Residue Monitoring Schedules for the Meads Creek, Stringers Cove, Zuidpool and Soldiers Point leases, in the D'Entrecasteaux Channel and Huon River Marine Farming Development Plan Area. These monitoring programs have generated more than 3,000 individual analytical results from water, sediment and wild fish samples collected under the different monitoring schedules.
“A significant body of scientific work is represented in these results and the EPA's ongoing review of the extensive data collected for the treatments at these leases continues to support the initial findings released by the EPA, and indicates the majority of the antibiotic administered is being taken up by salmon, with measured concentrations in the environment remaining very low and consistent with those previously reported," said Ms Murdoch.
Ongoing analysis of the results indicate that florfenicol and florfenicol-amine residues were found in 15 out of 1,274 sediment sample results. These samples contained trace levels of florfenicol and florfenicol-amine (ie, in parts per billion).
Similarly, florfenicol and florfenicol-amine residues were found in water samples in very low concentrations (within the parts per billion and parts per trillion range). More than 1,300 water sample results have been reported to the EPA, 12.5% of water sample results analysed outside of the lease boundary contained trace levels of florfenicol or florfenicol-amine. Florfenicol and florfenicol-amine residues were highest in surface and mid waters samples and decreased with distance from the lease. Florfenicol and florfenicol-amine were not reported in water samples 7 days after treatment.
Florfenicol-amine residues have been found in 13 of the 639 wild fish samples analysed. The latest results indicate that florfenicol and florfenicol-amine residues are not accumulating in the water or sediment components of the marine ecosystem.
The results of this monitoring will enable the EPA to complete an environmental risk assessment for the use of florfenicol in Tasmanian marine waterways. Components of the risk assessment are currently being peer reviewed, and the EPA anticipates that the finalised environmental risk assessment will be released in April 2026.
Monitoring will continue over the coming months in response to treatments at five additional marine farming leases in the D'Entrecasteaux Channel. The EPA will continue to actively release the results of the monitoring programs as the sampling is completed.
Testing results have been shared with the Department of Health throughout the environmental monitoring program.
The Director of Public Health, Dr Mark Veitch said “Florfenicol residue was detected in two wild finfish samples in November 2025. These Australian Salmon were caught within 1km of two leases on the day after treatment ended."
Commenting on subsequent testing, Dr Veitch said “Extensive sampling and testing related to other leases has detected florfenicol residue in a small number and small proportion of wild finfish samples. All these samples were collected within 1km of a treated lease, and no later than 7 days after treatment ended.
“Eating typical amounts of these wild finfish does not pose a risk to human health.
“Further testing of wild finfish, up to 3km from treated leases and up to 38 days after treatment, has not detected florfenicol residue.
“If a person chooses to avoid eating finfish that may contain florfenicol residue, they could choose to avoid eating wild finfish caught within 3km of a lease during treatment and for 21 days after treatment finishes."
“The very low levels of florfenicol residues detected in non-finfish species, such as abalone and the hepatopancreas of rock lobster, pose no risk to human health."
ENDS.
Published on:
6/03/2026