Global conservation of Tachypleus tridentatus: Present status and recommendations

Abstract

Horseshoe crabs are an ancient group of marine arthropods. The Chinese horseshoe crab (Tachypleus tridentatus) is the largest among the four extant species. Tachypleus tridentatus is regarded as the indicator species of estuarine ecosystems. Meanwhile, its blood is used to manufacture biomedical testing kits, i.e., Tachypleus amebocyte lysate. The geographic distribution of T. tridentatus is constrained to the western Pacific Ocean, ranging from the Seto Inland Sea of Japan southwards to the North Jawa waters. A high historical population size of T. tridentatus was recorded in eastern China and southern Japan. Tachypleus tridentatus population decline has become apparent since the 1950s, and the species has been upgraded to “Endangered (EN)” under the IUCN Red List in 2019, depicting its global declining trend. Habitat destruction and overfishing are identified as the primary threats. We reexamined current conservation measures targeting T. tridentatus, including marine protected area establishment, captive breeding and restocking, and awareness programs and regulations. We provide recommendations to enhance the conservation and management of global T. tridentatus populations through: (1) expediting population baseline data collection; (2) developing standards for population/habitat monitoring; and (3) establishing scientifically sound restocking programs.