When we think about cleaning the ocean, we often imagine divers removing ghost nets or volunteers collecting plastic from the shore. But beneath the surface, nature has its own recycling systems.

In this episode of our Ocean’s Natural Cleaning Crew series, we turn to one of the most overlooked and most underestimated marine animals: the sea cucumber.

Joining us is Prof Annie Mercier, Department of Ocean Sciences, Memorial University (Canada), who has spent decades studying these remarkable creatures and co-edited the comprehensive scientific volume The World of Sea Cucumbers.

The “earthworms” of the ocean

Sea cucumbers play a vital but often overlooked role in marine ecosystems. Like earthworms on land, they process seabed sediments, recycle nutrients, and help keep ocean floors oxygenated. On coral reefs, they may even support coral health by reducing harmful bacteria.

Despite their simple appearance, sea cucumbers are incredibly diverse, ranging from tiny species to over a meter long, and living in environments from shallow reefs to deep-sea trenches. Their biology is equally remarkable — some can regenerate organs, split in two, and live for decades, making them valuable for scientific research on aging and regeneration.

However, rising global demand has led to overfishing, putting many populations at risk. Losing them doesn’t just remove a species — it disrupts essential ecological processes that keep marine ecosystems balanced.

Sea cucumbers may not be iconic ocean animals, but they are quiet engineers of resilience — and far more important than we often realize.

🎧 Listen to the full episode to discover why these humble creatures matter so much.

Further links to the topic:

• IUCN SSC Sea Cucumber specialist Group: https://iucn.org/our-union/commissions/group/iucn-ssc-sea-cucumber-specialist-group
• Prof. Annie Mercier lab's website: https://www.mercier-lab.ca/
• The open-access conservation paper: https://doi.org/10.1146/annurev-marine-032123-025441
• Book https://www.sciencedirect.com/book/edited-volume/9780323953771/the-world-of-sea-cucumbers

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Healthy Seas is a marine conservation organization whose mission is to tackle the ghost fishing phenomenon and turn this waste into an opportunity for a more circular economy. They do this through clean-ups, prevention, education, and working with partners who recycle and repurpose this material. The podcast is hosted by Crystal DiMiceli.