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Rebuilding reefs – creating coral ‘reef stars’ in the Seychelles

We regularly see and hear about coral reefs in the news. It is usually a sad story, focused on coral bleaching and the reduction of coral cover in areas across the globe. But there are reasons to be hopeful, with many projects exploring ways to help protect and regrow coral reef. Earthwatch is working on one such exciting coral conservation project within our longstanding partnership with Mitsubishi Corporation. 

Coral reef stars being attached together on the sea floor © Noel Janetski

In a blog last year we talked about how we, with our partners, built a ‘coral nursery’ in the Seychelles, a refuge area where coral can grow quickly and safely. The nursery used local materials - such as concrete, rope and floats - to suspend branching corals, giving them a better opportunity to grow and spawn naturally, before being used to help the surrounding reefs. 

The precise business of measuring resin © Earthwatch

This year we have started taking the next step to transplanting the corals grown in our coral nursery out onto the degraded reef. We are working with Mars Sustainable Solutions team, who have developed the Mars Assisted Reef Restoration System, an innovative approach of coral ‘reef stars’.


Coral reef stars are steel structures, treated and coated in sand, which infant corals can be attached onto. The reef stars are then secured to the sea floor, building an intricate web around existing corals or across barren rubble beds. Using this approach, vast quantities of coral can be transplanted in a short period of time, in a ready-made ideal growing environment.

Coating the steel structures to ensure that they do not rust © Earthwatch

In March 2020, just before Covid-19 halted international travel, the team were able to visit the Seychelles to train our local partners, the Seychelles National Park Authority in how to make these coral reef stars. Mars have been building coral reef stars and rebuilding large areas of reef since 2011, but this is the first time this conservation technique has been brought to the Seychelles.

The detailed process of building the coral reef stars - from welding to painting to sand coating (to give the corals a substance to attach onto) - takes multiple days. Thankfully the 30+oC heat helped to speed up the drying phases!

The team coating the coral reef stars in sand © Earthwatch

Earthwatch has been in partnership with the Seychelles National Park Authority since 2006. With our research partner Dave Smith, from the Coral Reef Research Unit at the University of Essex, and our funding partner Mitsubishi Corporation, we have explored the coral of the Seychelles, discovering the existence of ‘super corals’ which are significantly more resilient to ocean warming events than other species, as well as refuge areas within Curieuse Marine National Park where corals have a higher survival rate.

We are excited to be taking this research forward into active conservation and bring together the decade of research into how certain reef areas and species are better able to withstand thermal events with best-proven practises of coral restoration. This new phase of the project aims to increase the abundance of heat-tolerant corals in refuge environments and the abundance of heat-tolerant species across other reef areas, as well as building in-country capacity. Through this project we hope to find solutions to coral loss and the impact of climate change.

A stack of reef stars – coated in sand and ready for corals to be attached onto them © Earthwatch


Due to the Covid-19 pandemic, we’ve had to push back the date to install these reef stars, which we will do in partnership with the Seychelles National Park Authority and with the support of Mitsubishi Corporation volunteers, but we are looking forward to being able to continue in 2021.

This next phase will involve attaching the coral from our nursery onto 100 of the reef stars and fixing them onto the sea floor within the refuge environment and across control sites that were devastated by the 2015-16 global thermal event that destroyed many reefs worldwide. Then, hopefully, we will only have to wait a few months until we see the corals growing and spreading across the reef!


Caroline Kluyver, Programme Manager

Originally published on LinkedIn



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