Population and ecology of Asian horseshoe crabs

The occurrence of horseshoe crabs and their ecology provide essential information on the well-being of coastal ecosystems. While there are studies on population abundance, density, and structure across their geographic range, there is a lack of consistency in monitoring techniques, precluding comparison of data in different areas and/or times. In this regard, methodologies ranging from the traditional quadrat/transect, capture-mark-recapture, to the more recent use of acoustic telemetry, biologging, unmanned aerial vehicles, and niche modeling are reviewed in terms of monitoring horseshoe crab population status, activity, and distribution. Ecological studies related to horseshoe crab habitat utilization, activity, home range, trophic relationships, interspecific interactions, and responses to environmental perturbations are also discussed. Future work should adopt a standardized monitoring protocol and integrate laboratory- and field-based approaches to elucidate how habitat changes affect the ecology of Asian horseshoe crabs. © 2026 Elsevier Inc. All rights reserved.