Longspined sea urchins are causing significant ecological damage along Tasmania’s east coast, transforming kelp-rich reefs into barren zones due to their expanding populations linked to climate change. While harvesting these urchins for their roe has become an effective control measure, the process leaves behind large volumes of waste—up to 90% of the animal—which typically ends up in landfill at a high cost.

Researchers from the Tasmanian Institute of Agriculture (TIA), in collaboration with the Institute for Marine and Antarctic Studies (IMAS), are exploring the potential to repurpose this waste as a soil ameliorant for agricultural use. Early trials, led by Dr Harriet Walker, show promising results: ground and dried sea urchin waste significantly increases soil pH and supplies beneficial micronutrients like calcium, boron, and iron, making it a viable alternative to synthetic fertilisers or commercial lime.

Field trials are underway across vineyards, apple orchards, and potato crops to test the long-term impacts of this treatment on soil health and crop productivity. Results from vineyards suggest that sea urchin waste maintains improved soil pH longer than standard lime products, with no negative impact on salinity. While yield differences are yet to be observed, the research supports the potential for a sustainable, circular economy approach that transforms a marine pest and seafood waste into a valuable agricultural input. The team is now working to commercialise the product for broader use across Tasmania’s agricultural sector.

Full University of Tasmania article available here: https://www.utas.edu.au/about/news-and-stories/articles/2025/from-sea-to-soil-transforming-sea-urchin-waste-into-fertiliser