Dosed-up Tasmanian salmon could pose health risks in the long run
In early April it was reported that Tasmanian salmon farmers have been using antibiotics to treat the bacteria that has killed over a million salmon, and that fish from diseased pens are being sold for human consumption.
Australians have been told it’s all fine, provided the fish are withheld from harvesting for the right time and the waterways aren’t flooded with antibiotic residue.
But it’s concerningly difficult to prove the former, and we know the latter is already happening. This is no longer a solely environmental issue – it’s a public health issue, too.
Mandatory withdrawal periods are written into several pieces of federal and state law. But it isn’t always clear who is supposed to administer them.
Under the Code of Practice for the Supply and Use of Veterinary Chemical Products, Biosecurity Tasmania (which is an agency within the Department of Natural Resources and Environment, or NRE) is responsible for all laws that affect biosecurity, including antibiotics for salmon.
In practice, Tasmania’s Environment Protection Authority has played the leading role in administering the withholding regulations. They are the ones receiving reporting and residue testing from infected salmon pens and nearby waterways, and they are handling the public relations work to boot.
DNRE says that withholding periods are “case- and antibiotic- specific”. The norm is 63 days, depending on average water temperatures. (It’s not clear if or how the department monitors temperature changes.)
You might like
The EPA simply requires companies to sample the water and sediment, and send them a report.
The responsibility for enforcing these rules ultimately rests with the federal Department of Agriculture, Fisheries and Forestry, which conducts “randomised and targeted testing programs”. The minister, Julie Collins, is herself a Tasmanian MP.
Food safety laws in Tasmania give the Director of Public Health significant powers for guarding against the handling and sale of unsuitable food, though these have not figured anywhere in public discussion. Nor, it should be said, has the Director himself.
Apart from deadly fish diseases, salmon pens are a perfect breeding ground for opaqueness. On their websites, all three companies operating in Tasmanian waters – Huon, Tassal and Petuna – assure readers that they adhere to “withholding periods” for treated fish, but none specify what that mandatory time period is nor how it is calculated.
There is no evidence proving one way or another whether the salmon companies are adhering to the Code.
Australian consumers should have access to testing conducted by public agencies (rather than the companies themselves) that can prove, one way or another, whether treated salmon have been withheld appropriately.
It is not good enough to ask the public to simply take it on trust, as community services minister Roger Jaensch did earlier this month.
What about antibiotic residues in the environment?
Stay informed, daily
When salmon farmers dose their fish with antibiotics, some residue is left in the waterways, which means it is consumed by other marine life.
During Huon Aquaculture’s recent round of antibiotic dosing, salmon were dying faster than they could consume the antibiotic pellets. Levels of antibiotics in the surrounding environment noticeably increased.
The EPA recently said that there was enough antibiotic residue in the water to justify further testing. It says there are “sound reasons for wanting as little contamination of our environments with antibiotics as possible, particularly to reduce the selection of antibiotic-resistant bacteria”.
The EPA is inconsistent with its releases of information. In February, it chose to treat Huon Aquaculture’s disclosures about the volume and location of antibiotic treatment as “commercial-in-confidence”.
This allows salmon farmers to choose their own level of self-reporting, which means the public has no verifiable knowledge about whether, or how much, antibiotics have been used.
Scientists, health experts and safe water advocates have warned that the health effects could be quite bad in the long run. ANU infectious diseases expert Peter Collignon told The Saturday Paper that too many antibiotics can lead to “resistance in other bacteria” and “the development and spread of superbugs”.
Greens, Independents and the Jacqui Lambie Network have brought the issue to the fore in Tasmania’s parliament, pointing out that one of the “single biggest threats that we have on the horizon is antibiotic resistance”.
Despite these health risks, Tasmania’s Department of Health has taken a back seat on this issue.
For its part, the Department of Health’s Public Health Services unit has said that “low quantities” of antibiotic residue in the environment do “not raise human health concerns” and that any risk can be eliminated by “washing with soap and water”.
The Department has washed its hands clean of the issue. Australian consumers don’t have that luxury. Biosafety requirements are there to protect the health of Australians, and perhaps governments should enforce them now so that public health isn’t jeopardised in the long run.
Dr Joshua Black is a Postdoctoral Research Fellow at The Australia Institute. You can read more from him and the institute here.
