Tasmanian based Sea Forest is the first business in the world to sustainably cultivate red seaweed at a commercial scale.
Methane is a potent greenhouse gas, and reducing its emissions could significantly mitigate climate change. Current research has found Asparagopsis, a species of red seaweed contains compounds that can significantly reduce methane emissions from livestock such as cows and sheep when added to their feed. To help manage the climate crisis, aquaculture companies like Sea Forest have been investigating the harvestability and cultivation of Asparagopsis species throughout Australia. Asparagopsis is primarily cultivated in Tasmania, however natural populations of an Aspargopsis seaweed is also found off the central coast of Queensland in the Great Barrier Reef Marine Park. Sea Forest has recently explored opportunities in Queensland to harvest natural populations to minimise the requirement for on-land cultivation.
The Great Barrier Reef Marine Park Authority (GBRMPA), responsible for the management and protection of the Great Barrier Reef Marine Park in Australia, granted Sea Forest a Marine Park permit that allowed for the harvesting of Asparagopsis in the Keppel Islands. However, the terms of the permit stipulated Sea Forest would need to provide evidence of Asparagopsis naturally regenerating with similar abundance and distribution following an annual cycle.
Our team was engaged to undertake the post-harvest surveys following almost a year’s worth of growth to assess recovery against pre-harvesting quantities using abundance and distribution as key metrics at three islands: Sloping Island, Humpy Island and North Keppel Island.
Diving into the task
The scuba dive was challenging because of the vastness of the assessment area and the relatively localised distribution of Asparagopsis. Conditions amongst sites, such as depth, current, substrate type were highly variable, so transect and site locations had to be modified in the field based on the distribution we observed at the control locations for each island. The team undertook monitoring, scribing results under the water while also using image capturing to assess any differences between scientists, a common way to assure us and the clients, the results we obtain are consistent throughout the monitoring effort. Data collected was used to assess Asparagopsis composition and whether populations and coverage within and outside of the harvest area were relatively consistent.
Having studied the data, areas harvested are comparable to non-harvested areas. However, we understand that due to the sparseness and random distribution of Asparagopsis in the Great Barrier Reef, in combination with the intensive area to harvest natural populations, Sea Forest has a preference to cultivate the Tasmania species on land.
The species that grows off the coast of Tasmania attach itself using hooks. Meaning it can attach itself to rope, much like muscles. The species that we studied has more of a root structure that needs to be buried into a substrate like sand or coral and can’t fix in the same way that the other species can, limiting commercial applicability to grow this particular species.
Asparagopsis cultivation offers a sustainable solution to reduce methane emissions from livestock and mitigate climate change. Its potential for wider adoption could lead to significant environmental benefits and economic opportunities in the future.
Contact Shannon Goodwin to learn more.