In many countries around the world, significantly the United States of America, Canada, Norway and Australia, over-grazing urchins are a contributing cause of kelp forest decline.  In our work to help with regeneration of kelp, at Down Deep Drones we have made significant progress in using our own tools on our ROVs and other commercially available underwater drones for the purpose of controlling, and also culling, over-grazing or invasive urchins and other marine pests.

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In Tasmania the Long-Spined Urchin, Centrostephanus rodgerii or Centro for short, has thrived in the warming waters and is aggressively over-grazing.

While it is well-known for its grazing on kelp, particularly Ecklonia radiata, and its role in creating "urchin barrens" by overgrazing macroalgae, Centro has a more diverse diet than just kelp:

Other macroalgae: This includes a variety of brown, green, and red algae, as well as coralline algae.

Drift algae: They will feed on any loose seaweed that drifts across the seafloor.

Microalgae: In urchin barrens where macroalgae are scarce, Centro can survive by feeding on the microalgae that grows on the rocky substrate.

Kelp gametophytes: These are the microscopic, early life stages of kelp.

Invertebrates: Gut content analyses have shown that their diet can also include molluscs

and crustaceans!

This diverse diet allows Centro to survive and even thrive in areas where kelp forests have been decimated, such as in urchin barrens. This ability to switch food sources contributes to their success and their significant impact on temperate reef ecosystems.

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On location in Tasmania, Australia, we have been trialing tools that attach on to commercially available underwater drones.  We have been able to cull the invasive urchins with our tools, and now at Down Deep Drones we will soon be able to determine how many urchins we can kill on average over an hour.  

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We are fortunate to have had financial assistance from the Abalone Industry Reinvestment Fund in Tasmania and have gratefully received a grant to continue our trials until April 2026.

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