Tasmania's EPA grants two-year extension for controversial Long Bay salmon farm

Tasmania's Environment Protection Authority (EPA) has granted a two-year extension for a salmon farm in a shallow bay near Port Arthur, despite community concern over its environmental impact.

Tassal restarted operations in Long Bay in 2017, before it was required to reduce its fish feed amounts by 20 per cent in 2023 following studies into reef health and water quality.

The EPA then undertook further monitoring to determine if the changes were reducing nutrient impacts on the surrounding ecosystem, before agreeing to extend the licence in a decision published this week.

The monitoring showed that ammonia and nitrogen levels were elevated at a site closest to the fish farm over summer, while nutrient levels reduced within weeks of the pens being seasonally emptied.

Levels of 'nuisance' algae were also elevated next to the site, but these levels were described by the EPA as "low", and that they had not increased from 2021 to 2025.

The impact this was having on an inshore reef area could not be fully determined due to a lack of benchmarking prior to the salmon farm operating.

Locals had also raised concerns about the loss of seagrass in the area.

The EPA found that three seagrass sites had declined from 2023 levels — when a 48-tonne nitrogen limit was introduced — but that "little is known" about how seagrass responds to fish farm nutrients.

The sample size was also considered low.

The EPA recommended further research into environmental variations in the shallow enclosed bay, comparisons with the broader Port Arthur and Storm Bay areas, and to further measure changes since 2023.

Algae growth driven by water temperature, EPA says

The EPA pointed to shallow water temperatures — rather than fish farm nutrients — as being the driver of algae growth.

It argued that Port Arthur and Long Bay are interconnected with offshore water masses, such as the Southern Ocean, which resulted in nutrient exchange.

"The effect of shallow water temperatures on algal growth … does not support that persistent nuisance algal blooms are being caused by fish farming," the EPA decision reads.

The Tasmanian Independent Science Council (TISC) was among more than 80 submissions against the lease extension; the council met with the EPA in January to discuss its concerns.

The TISC argued that Long Bay is unsuitable for salmon farming due to it being "poorly flushed" and sheltered, and that the vast majority of human-caused nutrient loads in the bay could be attributed to the salmon farm.

It questioned how monitoring studies had been designed, and that the EPA had taken a "continuous improvement" approach rather than a precautionary one.

"The baseline surveys … did not include any monitoring sites in the poorly flushed northern areas of the bay, and most of the reports do not provide any context as to the timing and magnitude of farming operations," the TISC told the EPA.

Locals provided the EPA with algal mats — a dense layer of algae which forms in water — which the EPA described as "anecdotal evidence" and argued that similar occurrences are noted in areas without salmon farms.

"The EPA prefers a science-based approach whereby specific photo points are assigned, and images are captured without bias through seasons and over an extended time frame," its decision reads.

Company welcomes extension

Tassal welcomed the EPA's decision to allow salmon farming at the site to continue for at least another two years.

The company described the EPA's assessment as "one of the most comprehensive … in Tasmania's marine farming industry".

Tassal had committed two environmental breaches at the Long Bay lease site, which the EPA described as "short-lived and … rare".

The EPA also had to consider Tassal's overall compliance levels in Tasmania; the company has 18 marine farm environmental licences in the state, four freshwater hatcheries and four processing sites.

It has been issued environmental notices for feed dumping at its Soldiers Point site in 2021, a diesel spill at Margate in 2022 which it did not report, effluent quality issues at its Karanja hatchery, and pollutant discharges at its Triabunna rendering site.

It had received 14 formal warning notes since 2021, and 33 convictions for non-environmental matters — the vast majority relating to marine debris offences.

The Tasmanian Greens and environmental groups slammed the EPA's decision to extend the Long Bay lease.

Greens leader Rosalie Woodruff said she disputed a range of the EPA's conclusions, and the way monitoring had been carried out since 2017.

"Any assessment of environmental harms that have occurred since then has started after salmon companies have already been making changes to that beautiful waterway."