Two species of horseshoe crab can be found in Singapore – the mangrove horseshoe crab, Carcinoscorpius rotundicauda and the coastal horseshoe crab, Tachypleus gigas. Carcinoscorpius rotundicauda is listed as Vulnerable while T. gigas is listed as Endangered in the Singapore Red Data Book (Davison et al., 2008).

Objective: This NParks project aims to determine the population distribution of horseshoe crabs in Singapore

When it started: May 2013

Approach: Horseshoe crabs were surveyed at 18 intertidal sites in Singapore using belt-transect and rapid assessment methods. The species’ abundance, size and sex ratios were recorded in the NPark’s survey. The results of the survey will provide baseline information on the distribution of horseshoe crabs in Singapore that can facilitate their conservation and management.

A mangrove horseshoe crab Carcinoscorpius rotundicauda found at Kranji Dam, one of the 18 survey sites studied.

Horseshoe crabs were sometimes found trapped in ghost nets.

A comparison between an adult (left) and juvenile (right) horseshoe crab.