Antibiotic name and dosing period
Florfenicol 100% Active. Four 10-day treatments under 4 Veterinary Authorities (2 at each lease), with the first treatment starting on 24 January 2026 at MF203 and the final treatment finishing on 3 March 2026 for both MF185 and MF203.
The results for each monitoring program for both leases were reported together because several of the sampling locations were shared due to the leases geographical proximity to each other.
Summary of sampling rounds undertaken
The original monitoring schedules required that water, seabed sediment and wild fish samples were collected immediately after treatment (day 1 post-treatment, day 7 post-treatment, day 14 post-treatment, day 21 post-treatment).
Addenda to the Monitoring Schedules were issued due to the receipt of additional Veterinary Authorities for these leases. The addenda required that these samples be collected weekly until all treatments on the lease had finished and 2 consecutive results below the limit of reporting were received and the Director had authorised that sampling be stopped.
Samples were collected at sites both inside the leases (pen bays and centroids) and outside the leases, including compliance sites, transect sites, and reference sites.
In total, 222 individual wild fish samples were caught and analysed across 4 zones (within 1 km, between 1-3 km and greater than 3 km) from the lease boundaries. The 222 wild fish samples included 8 benthic and pelagic species, being sand flathead, blue-throated and purple wrasse, pike, barracouta, mackerel, barber perch and Australian salmon. Sand flathead, blue-throated wrasse and barracouta were the most commonly captured species.
In total, 115 sediment samples and 249 water samples were collected and analysed at multiple distances from the pen bays and including reference sites up to approximately 5.3 km from the lease boundaries.
Assessment of compliance against the schedule issued by the EPA
The report is compliant with the requirements of the Therapeutant Residue Monitoring Schedule - MFL 185 - Great Taylors Bay 1 - February 2026, the ADDENDUM - Therapeutant Residue Monitoring Schedule - MFL 185 - Great Taylors Bay 1 - 27 February 2026, the Therapeutant Residue Monitoring Schedule - MFL 203 - Great Taylors Bay 2 - January 2026, the ADDENDUM - Therapeutant Residue Monitoring Schedule - MFL 203 - Great Taylors Bay 2 - 27 February 2026, section 28(2) of the Environmental Standards for Tasmanian Marine Finfish Farming 2023 and any minor variations approved by the EPA Director.
Summary of findings in report
The results outlined in this report mostly align with the EPA's Preliminary analysis of environmental samples for florfenicol in southern Tasmania , as the vast majority of samples collected and analysed had florfenicol and/or florfenicol amine concentrations below the limit of reporting
Two sediment samples collected from treated pen bays had florfenicol or florfenicol amine equal to the limit of reporting on day 7 and week 2, respectively, at Great Taylors Bay 2. All sediment samples collected from external and reference sites had florfenicol and florfenicol amine concentrations below the limit of reporting.
Water samples with florfenicol and/or florfenicol amine concentrations above the limit of reporting were collected from some internal and external compliance sites on day 1 and in week 1. All water samples collected after this had florfenicol and/or florfenicol amine concentrations below the limit of reporting.
Four wild fish samples captured within 1 km of the leases had concentrations of florfenicol and metabolites as florfenicol amine above the limit of reporting in week 1.
EPA's assessment of potential environmental impacts
The EPA has completed a significant body of work to establish a guideline value for ecotoxicity of florfenicol in aquatic environments and has reviewed all of the water and sediment data collected under florfenicol residue monitoring schedules against this guideline value. The EPA has found that florfenicol residues present low risks to aquatic ecosystems. For further information, including a detailed scientific report, please see Environmental risk assessment of florfenicol use in marine salmonid aquaculture in SE Tasmania 2025 – 2026.
Statement from the Director of Public Health
Public Health Services notes the reports of florfenicol residue detected in 4 of 12 wild finfish samples (all barracouta) caught within 1 km of 2 treated leases during the last days of treatment at the 2 closely located leases. Eating typical amounts of these wild finfish does not pose a risk to health. Florfenicol residue was not detected in any of 24 wild finfish samples caught more than 3 km from the lease on the same days.
A further 186 wild finfish samples were caught before and after the positive samples and were tested for Florfenicol residue in relation to these four treatment events (2 overlapping in time) at 2 closely located leases. These comprised 54 samples caught within 1 km of the treated leases, and 132 caught more than 1 km from the treated leases. Florfenicol residue was not detected in any of these samples.
Public Health Services has reviewed all results to date and maintains its precautionary advice, which is available on the Department of Health website.
Link to final report:
Final Report - Therapeutant Residue Monitoring Program - MFL 185 and 203 Great Taylors Bay 1 and 2 (PDF 3Mb)