Horseshoe Crab Rescue & Research Programme


Since 2007, this 11-year-old initiative started as a conservation effort to rescue Horseshoe Crabs entrapped in deployed and abandoned fishing nets at the Mandai mudflats. It then evolved to basic research and on to more sophisticated research to improve our understanding of this little-known ancient mariner, the Horseshoe Crab, which is as old as the dinosaurs.

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Over the years, we have had students from primary and secondary schools, junior colleges, international schools and tertiary institutions collaborating in rescue and research on the Mandai mudflats. This activity is a real immersion in "muddy hands-on and legs in mud" and "out of the comfort zone" search and, if necessary, rescue work. We introduce and train volunteers in the discipline of proper handling of the Horseshoe Crabs, measuring, identifying, marking, recording, releasing them back into the mangroves and recapture techniques. They may also be involved and assist with data analysis to help determine population size and density. A census in 2009 all around Singapore made a first attempt to determine which were the areas where Horseshoe Crabs could be found to create a preliminary map all of the locations in Singapore where there are sizable colonies of our 2 species of Horseshoe Crabs and to use this as a baseline for a yearly census. A related interview activity with local fishermen also increased knowledge of horseshoe crab activities. In December 2010, a six-month study monitoring the movements of Horseshoe Crabs in the Straits of Johor using radio transmitters was also carried out.


Our mission is to better understand the Horseshoe Crab, create awareness of their importance to the mangrove habitat and device strategies, education and otherwise, to prevent their decline and, perhaps, inevitable march to extinction.  

This initiative has been funded by Caterpillar Foundation and IKEA Singapore.

We are proud to announce that we have published five research papers:

1) Population structure and breeding pattern of the mangrove horseshoe crab Carcinoscorpius rotundicauda in Singapore

2) Distribution and abundance of horseshoe crabs Tachypleus gigas and Carcinoscorpius rotundicauda around the main island of Singapore

3) Follow-up study on population structure and breeding pattern of the mangrove horseshoe crab Carcinoscorpius rotundicauda in Singapore

5) Studies of horseshoe crabs around Singapore

We thank all our volunteers who contributed their time and effort in data collection and analysis to help make the publication of the papers possible. We hope to publish more exciting research findings in future.

Below are articles and updates on the Horseshoe Crab Rescue and Research Project published in our Nature Watch Magazine:

NSS' Motion Adopted at World Conservation Congress

The motion for the conservation of Asian horseshoe crabs (Tachypleus tridentatus, Tachypleus gigas and Carcinoscorpius rotundicauda) was successfully adopted at the IUCN World Conservation Congress in Jeju, Republic of Korea, 6–15 September 2012.

Nature Society (Singapore) was the main sponsor of the motion.

Co- Sponsors were:

· Asia Pacific Centre for Environmental Law, Singapore

· Centre for Environmental Legal Studies, PACE University, USA

· Bombay Natural History Society, India

· Haribon Foundation for the Conservation of Natural Resources, Philippines

· Malaysian Nature Society, Malaysia

NSS’ IUCN Coordinator, Mr Vinayagan Dharmarajah, who had actively spearheaded the motion on behalf of NSS, represented NSS at the Congress.

The full motion can be found at the link below:

The complete list of Resolutions & Recommendations adopted by the IUCN during the 2012 World Conservation Congress can be found at:

Our motion for the conservation of the Asian Horseshoe Crabs can be found on page 41-43 of the booklet.

Horseshoe Crab Rescue & Research Related News

Feb 25, 2013

Import Bans Sought on Asian Crabs
by John Hurdle
The New York Times

An interstate panel warns that imported horseshoe crabs pose a threat to the already threatened variety on the Atlantic Coast.

To read the full article, click here.

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