Antibiotic name and dosing period(s)
Florfenicol 100% Active. Two 10-day treatments under 2 Veterinary Authorities, with the first treatment starting 10 February until 19 February 2026, and the second treatment starting 22 February until 3 March 2026.
Summary of sampling rounds undertaken
The original Monitoring Schedule required that water, seabed sediment and wild fish samples were collected immediately after treatment (day 1 post-treatment, day 7 post-treatment, and day 21 post-treatment).
An Addendum to the Monitoring Schedule was issued due to the receipt of an additional Veterinary Authority for this lease. The Addendum 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 lease (pen bays and centroids) and outside the lease, including compliance sites, transect sites, and reference sites.
In total, 168 individual wild fish samples were caught and analysed across 2 zones (within 1 km and at 2 reference sites) from the lease boundaries. The 168 wild fish samples included 11 benthic and pelagic species, of which blue-throat wrasse, sand flathead (until 1 March 2026), Australian salmon, barracouta and purple wrasse were the most commonly captured species.
In total, 54 sediment samples and 180 water samples were collected and analysed at multiple distances from the pen bays and including reference sites up to approximately 9.2 km from the lease boundary. Weekly samples collected at BEMP site M9 were approved to be used for the monitoring programs for both the Redcliffs and Great Taylors Bay leases.
Assessment of compliance against the schedule issued by the EPA
The report is compliant with the requirements of the Therapeutant Residue Monitoring Schedule – Marine Farming Lease No. 201 (Roaring Beach / 'Redcliffs') – February 2026, the Addendum - Therapeutant Residue Monitoring Schedule – Marine Farming Lease No. 201 (Roaring Beach / 'Redcliffs') – 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.
A total of 3 sediment samples collected from treated pen bays had florfenicol concentration equal to or above the limit of reporting in week 1, week 2 and week 3. 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 in week 1 and 2. All water samples collected afterwards had florfenicol and/or florfenicol amine concentrations below the limit of reporting.
Two wild fish samples captured within 1 km from the lease boundary had concentrations of florfenicol and metabolites as florfenicol amine above the limit of reporting in week 3.
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 2 of 12 wild finfish samples (both mackerel) caught within 1 km of a treated lease on 12 March 2026. This day was 22 days after the first treatment event and 9 days after the second treatment event at the lease. Eating typical amounts of these wild finfish does not pose a risk to health. Florfenicol residue above the level of reporting was not detected in 24 finfish caught more than 3 km from the lease on the same day.
Earlier sampling during the 2 weeks after the first treatment event and coinciding with the second treatment event at the lease – of 30 wild finfish samples caught within 1 km of the lease, and 60 wild finfish samples caught more than 3 km from the lease – did not detect Florfenicol residue above the level of reporting.
Florfenicol residue was not detected in any of 24 wild finfish samples caught within 1 km of the lease, or in any of 24 wild finfish samples caught more than 3 km from the lease, at least 27 days after the first treatment event and 14 days after the second treatment event.
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 201 Redcliffs (PDF 3Mb)