Located in the Central Highlands, Woods Lake plays an important role in generating energy for Tasmanians, as well as providing valuable irrigation water to downstream users. Woods Lake is also renowned for its trout fishing.
There has been an ongoing blue-green algae (cyanobacteria) bloom at Woods Lake since February 2023. This bloom is non-toxic and fishing is allowed. Read below for more information on the bloom, what we're doing about it and advice for recreational use of the lake.
Woods Lake bloom - Spring 2024 Update 2
Sampling results from September and October have not detected the species that has caused the recent blue-green algal bloom.
Whilst the bloom has subsided for now, it is important to continue to wash fish and take appropriate biosecurity precautions when out on the lake and moving between lakes – good practice is to clean all equipment between lakes, including washing down boats as the bloom may recur over summer and autumn.
As stated in the previous update, unfortunately this does not mean that the bloom will not reappear. when conditions are right (e.g., temperature, light levels and other environmental factors).
Recently several anglers have informed us that angling is improving on the lake and that we are starting to see growth of aquatic plants in some regions of the lake. We are hoping these conditions continue to improve and encourage a more diverse ecosystem within the lake
Heading out on the lake this spring/summer, and notice something we should know about? Ask a question below or reach out to Sarah and let us know!
Woods Lake bloom - Spring 2024 Update 1
Our last water samples showed that the bloom at Woods Lake has declined substantially. A decline in blue green algal cells also occurred at this time last year; however, this year's decline appears to greater. Unfortunately, this does not mean that the bloom will not reappear when conditions are right (e.g., temperature, light levels and other environmental factors).
Our team will continue to regularly monitor lake conditions and collect water samples. In addition, modelling work with the scientific panel is ongoing.
We thank you for your patience and will provide additional updates when anything new is available.
Woods Lake bloom - Winter 2024 Update
The bloom is continuing to persist in the lake despite measures taken to dilute the concentration of algal cells and, instead, promote aquatic plant growth. We expect that blue-green algae may continue to be present at Woods Lake for some time to come.
- The blue-green algae population continues to persist into July.
- Cell numbers may decline as a result of recent inflows providing dilution combined with sustained low temperatures.
- We expect the population may reduce and then re-emerge in summer as occurred from December 2023.
- Whilst the bloom may reduce in concentration and become less dominant, it is expected that when environmental conditions are optimal the residual population will again go through a rapid growth phase, as seen in the graph below over the last couple of years.
This chart represents the concentration of the current dominant bloom species (Dolichospermum sp.) collected from water samples from woods lake and analysed in the lab. The species has dominated the ecosystem since cells numbers grew rapidly from late February 2023.
Releases into the Lake River from Woods Lake have ceased over the winter period so will see a natural rise in the water level with local catchment inflows.
Fishing is permitted in the lake, but entrails should be disposed of and not left for wildlife.
Blue-green algae (cyanobacteria) bloom at Woods Lake.
Check out the widget on the right hand-side for more information on what blue-green algae is.
What caused this recent blue-green algae bloom?
At Woods Lake, consecutive years of La Nina may have contributed to a larger amount of naturally occurring nutrients flowing into the catchment and lake. However, there are also a range of other possible contributing factors that we are investigating with an expert scientific panel.
What does this mean for you?
While the bloom is non-toxic, direct contact or consumption of blue-green algae can pose a health risk.
People are advised not to enter the water and to avoid exposure to water spray if boating on the lake.
If you do have significant contact with the water, wash yourself down with clean water to remove any algae. Wash all clothing and equipment with clean water.
Any fish caught can be consumed but should be washed in clean water, gilled, gutted and all internal organs disposed of. Care should be taken that animals are not fed or allowed to eat the entrails of these fish. This is a precautionary measure as if there happened to be any toxins present, they can accumulate within the internal organs of fish and cause animals to become ill.
Good practice is to clean all equipment between lakes, including washing down boats, to do our collective best to prevent the spread of blue green algae.
What we are doing about it
We’ve been working closely with a range of external experts including representatives from the University of Western Australia (UWA), Griffith University and the University of Tasmania to investigate the drivers of the bloom and provide guidance around potential mitigation or management measures.
Based on this expert advice, we have previously drawn down water levels in an attempt to dilute concentrations of cyanobacteria (blue-green algae) and to encourage the growth of aquatic plants by enabling sunlight to reach the sediment.
Our expert panel has found the strain of blue-green algae isolated from Woods Lake has an optimal temperature of 25°C where maximum growth occurs, but also has an unusually high tolerance to low temperatures.
We’re hoping in time, management measures will help shift the lake from a blue-green algae dominated and murky system to the clear, plant dominated system you’re used to.
We’re also working with our colleagues at UWA to develop scientific models to assist with early identification of blooms in future and how best to manage future scenarios using available levers at our disposal.
Our current monitoring program consists of a combination of fortnightly manually collected water samples for analysis in the lab and a permanent water quality raft that collects and transmits data every 15 minutes.
Water quality parameters monitored include:
- Nutrients including dissolved nutrients.
- Water temperature
- Turbidity (clarity)
- pH
- Dissolved oxygen
- Electrical conductivity
- Algae and blue-green algae cell counts / identification
- Suspended solids
- Organic carbon
Located in the Central Highlands, Woods Lake plays an important role in generating energy for Tasmanians, as well as providing valuable irrigation water to downstream users. Woods Lake is also renowned for its trout fishing.
There has been an ongoing blue-green algae (cyanobacteria) bloom at Woods Lake since February 2023. This bloom is non-toxic and fishing is allowed. Read below for more information on the bloom, what we're doing about it and advice for recreational use of the lake.
Woods Lake bloom - Spring 2024 Update 2
Sampling results from September and October have not detected the species that has caused the recent blue-green algal bloom.
Whilst the bloom has subsided for now, it is important to continue to wash fish and take appropriate biosecurity precautions when out on the lake and moving between lakes – good practice is to clean all equipment between lakes, including washing down boats as the bloom may recur over summer and autumn.
As stated in the previous update, unfortunately this does not mean that the bloom will not reappear. when conditions are right (e.g., temperature, light levels and other environmental factors).
Recently several anglers have informed us that angling is improving on the lake and that we are starting to see growth of aquatic plants in some regions of the lake. We are hoping these conditions continue to improve and encourage a more diverse ecosystem within the lake
Heading out on the lake this spring/summer, and notice something we should know about? Ask a question below or reach out to Sarah and let us know!
Woods Lake bloom - Spring 2024 Update 1
Our last water samples showed that the bloom at Woods Lake has declined substantially. A decline in blue green algal cells also occurred at this time last year; however, this year's decline appears to greater. Unfortunately, this does not mean that the bloom will not reappear when conditions are right (e.g., temperature, light levels and other environmental factors).
Our team will continue to regularly monitor lake conditions and collect water samples. In addition, modelling work with the scientific panel is ongoing.
We thank you for your patience and will provide additional updates when anything new is available.
Woods Lake bloom - Winter 2024 Update
The bloom is continuing to persist in the lake despite measures taken to dilute the concentration of algal cells and, instead, promote aquatic plant growth. We expect that blue-green algae may continue to be present at Woods Lake for some time to come.
- The blue-green algae population continues to persist into July.
- Cell numbers may decline as a result of recent inflows providing dilution combined with sustained low temperatures.
- We expect the population may reduce and then re-emerge in summer as occurred from December 2023.
- Whilst the bloom may reduce in concentration and become less dominant, it is expected that when environmental conditions are optimal the residual population will again go through a rapid growth phase, as seen in the graph below over the last couple of years.
This chart represents the concentration of the current dominant bloom species (Dolichospermum sp.) collected from water samples from woods lake and analysed in the lab. The species has dominated the ecosystem since cells numbers grew rapidly from late February 2023.
Releases into the Lake River from Woods Lake have ceased over the winter period so will see a natural rise in the water level with local catchment inflows.
Fishing is permitted in the lake, but entrails should be disposed of and not left for wildlife.
Blue-green algae (cyanobacteria) bloom at Woods Lake.
Check out the widget on the right hand-side for more information on what blue-green algae is.
What caused this recent blue-green algae bloom?
At Woods Lake, consecutive years of La Nina may have contributed to a larger amount of naturally occurring nutrients flowing into the catchment and lake. However, there are also a range of other possible contributing factors that we are investigating with an expert scientific panel.
What does this mean for you?
While the bloom is non-toxic, direct contact or consumption of blue-green algae can pose a health risk.
People are advised not to enter the water and to avoid exposure to water spray if boating on the lake.
If you do have significant contact with the water, wash yourself down with clean water to remove any algae. Wash all clothing and equipment with clean water.
Any fish caught can be consumed but should be washed in clean water, gilled, gutted and all internal organs disposed of. Care should be taken that animals are not fed or allowed to eat the entrails of these fish. This is a precautionary measure as if there happened to be any toxins present, they can accumulate within the internal organs of fish and cause animals to become ill.
Good practice is to clean all equipment between lakes, including washing down boats, to do our collective best to prevent the spread of blue green algae.
What we are doing about it
We’ve been working closely with a range of external experts including representatives from the University of Western Australia (UWA), Griffith University and the University of Tasmania to investigate the drivers of the bloom and provide guidance around potential mitigation or management measures.
Based on this expert advice, we have previously drawn down water levels in an attempt to dilute concentrations of cyanobacteria (blue-green algae) and to encourage the growth of aquatic plants by enabling sunlight to reach the sediment.
Our expert panel has found the strain of blue-green algae isolated from Woods Lake has an optimal temperature of 25°C where maximum growth occurs, but also has an unusually high tolerance to low temperatures.
We’re hoping in time, management measures will help shift the lake from a blue-green algae dominated and murky system to the clear, plant dominated system you’re used to.
We’re also working with our colleagues at UWA to develop scientific models to assist with early identification of blooms in future and how best to manage future scenarios using available levers at our disposal.
Our current monitoring program consists of a combination of fortnightly manually collected water samples for analysis in the lab and a permanent water quality raft that collects and transmits data every 15 minutes.
Water quality parameters monitored include:
- Nutrients including dissolved nutrients.
- Water temperature
- Turbidity (clarity)
- pH
- Dissolved oxygen
- Electrical conductivity
- Algae and blue-green algae cell counts / identification
- Suspended solids
- Organic carbon