TAIPEI (Taiwan News) — The Ministry of Agriculture Fisheries Research Institute released on Friday 2,000 tri-spine horseshoe crabs in the waters off Penghu to support the species’ recovery in the wild.

The release marked International Horseshoe Crab Day and is part of an ongoing conservation effort that began in 2006, per CNA. Since then, the institute has regularly released captive-bred horseshoe crabs into suitable coastal habitats.

The tri-spine horseshoe crab, considered a "living fossil”, has existed for more than 400 million years. Its blue blood is medicinally valuable due to its unique ability to detect bacterial toxins.

However, the species faces increasing threats from overfishing, habitat loss, and slow reproduction rates. The International Union for Conservation of Nature currently lists the tri-spine horseshoe crab as endangered and has put it on its Red List.

The Fisheries Research Institute noted that tri-spine horseshoe crabs inhabit shallow, sandy seafloors. Females are typically larger than males, and males are often seen clinging to the backs of females, leading to their local nickname “couple fish” or “lover fish.”

The institute also reported that it has domesticated wild tri-spine horseshoe crabs and developed the ability to breed them in captivity. It holds the world record for the oldest horseshoe crab raised in captivity, 16 years.

To further protect the species, fishing for horseshoe crabs is banned in Kinmen and Lienchiang counties. In 2022, the Penghu County government also prohibited horseshoe crab harvesting, except for purposes related to research, education, or resource assessment.

Horseshoe crabs must molt multiple times before reaching sexual maturity. Males require approximately 13 years and 16 molts, while females take about 14 years and 17 molts. This long maturation period presents a significant challenge for conservation.