IMAS scientists have recently closed several key data gaps for the red seaweed species, Asparagopsis armata, which is at the centre of an emerging aquaculture industry due to its potential to contribute to global methane emissions reductions.

The Asparagopsis Bioregional Project, a partnership between IMAS scientists, the Department of Natural Resources and Environment Tasmania and Sea Forest, recently concluded, having uncovered detailed information about the distribution, reproductive status and genetic structure of Asparagopsis populations around Tasmania.

When added as a livestock feed supplement, compounds in Asparagopsis have been shown to dramatically reduce livestock methane emissions.

Click here to view the full news story, which includes the project's key findings.

The final project report can be found here.

This project was supported with funding from the Marine Bioproducts Cooperative Research Centre (MBCRC), the Department of Natural Resources and Environment Tasmania (NRE Tas), Sea Forest Ltd and the University of Tasmania. NRE Tas support came through the Sustainable Marine Research Collaboration Agreement between the Tasmanian Government and UTAS.

As our climate changes, marine heatwaves are becoming more frequent and longer lasting, with potentially severe impacts on marine ecosystems and the fisheries they support. This could include changes to the survival, behaviour and distribution of marine species targeted by commercial fishing, along with the food sources they rely on. South-eastern Australia is recognised as a climate change hotspot predicted to experience more severe marine heatwaves over the coming years. 

So, how can we safeguard our valuable fisheries against the impacts of marine heatwaves?  

Ocean temperature observations and forecasts are continually improving, however, often occur only on a scale that is too coarse to be useful for commercial fishers and marine farmers. 

Recently, IMAS partnered with commercial fishers from the octopus, scalefish and rock lobster fisheries to deploy temperature loggers on fishing gear off Tasmania’s east coast during a marine heatwave event. More than 70,000 temperature measurements were taken over 220 logger deployments between February and May 2024. 

This enabled water temperature data to be collected at the locations and depths relevant to fishers and to be compared with satellite temperature observations and the local marine heatwave status at the time of deployment. This data was then provided back to the fisher by way of an individualised report. 

Water temperatures were generally found to be warmer in the north of the state compared with the south. Sub-surface water temperatures collected by the loggers were often cooler than satellite-derived sea surface temperatures, except for at a few locations north of Flinders Island and around King Island at certain times. 

This project was successful in trialling methods to collect fine-scale sub-surface temperature data across a large area. Future streamlining and application of these methods will improve the accuracy of ocean temperature data, giving fishers an insight into the role temperature plays in affecting their catch rates and helping them understand and adapt to shifting local conditions. 

The full report can be accessed here.

IMAS would like to thank all the commercial fishers who were involved in this study. This project was funded by the Fisheries Research and Development Corporation (FRDC) and Tasmania’s Department of Natural Resources and Environment (NRE). 

Our seaweed scientists are mapping the distribution, abundance and chemical variation of Asparagopsis armata around Tasmania to support a budding aquaculture industry that’s helping reduce livestock methane emissions, as IMAS Ecology and Biodiversity Deputy Centre Head and project lead, Associate Professor Jeff Wright explains.

Asparagopsis is a small red seaweed that’s native to Tasmania. Sea Forest is the only Tasmanian company producing this seaweed for use as a feed supplement to help reduce livestock methane production in the agricultural sector.

The IMAS team is collecting data that will allow Sea Forest to identify and target sites with high-quality Asparagopsis that can be used as seed stock for cultivation at either their Triabunna or Swansea farms.

This research will also determine whether different genetic strains exist in Tasmania and whether these strains have different bioactive potential.

Bioactives are natural compounds that Asparagopsis produce to fight bacteria in the ocean, but these compounds also inhibit the bacteria that produce methane in the rumen of cows and sheep. The inhibition of these bacteria reduces methane emissions.

The information gathered in this project will also assist the Department of Natural Resources and Environment Tasmanian (NRE Tas) with managing Asparagopsis seedstock collection.

Tackling a global farming challenge…

Methane production from farmed livestock is a significant contributor to global greenhouse gas emissions.

Asparagopsis is a potential solution to this issue as it produces bioactive compounds that, when fed in small amounts to cattle and sheep, can reduce methane emissions by up to 98% – and this is why it’s been identified as a species with significant commercial livestock feed potential.

While Asparagopsis is native to Tasmania, we currently don’t have basic information on where it grows, its seasonal patterns of abundance, reproduction and bioactive compounds, and whether there are genetically different strains. The overall aim of this project is to address these knowledge gaps.

Diving into the sea for answers…

To tackle these questions, our IMAS field research team, led by our Ecology and Biodiversity Research Assistant Charley McAneney, is sampling and comparing bioregional and seasonal variations of Asparagopsis at 15 sites across five Tasmanian regions over a 12-month period.

They are using an underwater towed video camera (see video below), photographs and diver surveys.

This allows us to map Asparagopsis distribution and abundance and to collect seaweed samples for analysis of the bioactive compounds that cause methane reduction. We’ll also use these samples for analysing Asparagopsis genetics and reproduction.

Researchers have completed the first sampling period, with sites in the D’Entrecasteaux Channel, Port Arthur, Coles Bay, the Furneaux Group and north coast all surveyed. Our final sampling period will be between February and April next year, with the project to wrap up around July 2024.

Only the best for our livestock and planet…

This project will enable Sea Forest to identify and target high-quality seedstock for farming and determine whether there’s bioactive diversity in different genetic strains around Tasmania.

You can find out more about marine bioproducts here.

Author: Alex Luttrell