Developing novel seaweed cultivars from wild populations (Innovative Seaweed Aquaculture project ASTEC)
Seaweeds form some of the most productive systems in the marine environment. They support an immense diversity of species, provide valuable ecosystem services, and play an important role in mitigating climate change as major carbon sinks. Seaweed cultivation offers the potential for a nature-based, carbon neutral, and climate resilient solution to restore seaweed communities globally. Upscaling seaweed production offers a new, powerful approach to enhance community resilience, re-build natural seaweed communities, increase biodiversity, and enhance ecosystem services. It can also provide a socially acceptable means of restoring a communities’ local environment whilst maintaining economically sustainable livelihoods.
Eucheumatoids are tropical red seaweeds frequently used in the food and cosmetics industries. Increases in pest and disease outbreaks due to accelerating climate change, loss of genetic diversity, and biosecurity issues have led to seaweed production in Malaysia declining by 45% between 2012 and 2020, with catastrophic socio-economic impacts on the communities reliant on seaweed production. To address these challenges, there is an urgent need for new temperature-resilient cultivars derived from indigenous wild stocks, which can enhance the climate resilience of cultured stocks.
This project works with indigenous seaweed farming communities in Malaysia to collect populations from the wild for domestication trials at a research farm in Sabah. This has resulted in the discovery of new temperature-resilient cultivars that are brought into cultivation to enhance the climate resilience of cultured stocks in Malaysia. This is crucial to ensure the sustainability of the eucheumatoid industry despite the global climate change issues.
The major challenge during the project was the impact of the water currents on farmed seaweeds. The conventional method of tying the seaweeds onto the cultivation lines using plastic ties (called ‘tie-ties’) led to high levels of seaweed loss from the lines and increased fish and turtle predation. Consequently, growth rates could not to be measured. To solve this problem, the wild eucheumatoids were placed into the nylon nets. Unfortunately, this method also proved ineffective as silt from the seabed covered the nets and smothered the seaweeds.
Following discussions with the local farmers, new baskets were deployed with a larger mesh-size to prevent the entrapment of silt. The eucheumatoids were placed into the new nets for 2-3 weeks to enable sufficient growth before tying onto the cultivation lines. This solved the problem and reduced the effects of fish and turtle predation.
Lessons learnt and next steps
The outcome of this project was to develop new temperature-resilient cultivars that can be used by seaweed farmers in Malaysia. A system was developed for coastal seaweed cultivation of new cultivars that can be replicated throughout Malaysia. Site selection, however, was found to be extremely important, particularly the levels of siltation in the water column, which can suppress eucheumatoid growth rates.