Okayama: Catch of Live Horseshoe Crabs Hits 35-year High

The Yomiuri Shimbun

15:40 JST, June 7, 2025&

KASAOKA, Okayama — A total of 75 live horseshoe crabs were caught in the sea near Kasaoka, Okayama Prefecture, in fiscal 2024, the highest number for 35 years and an encouraging sign for the arthropod’s population there.

The area is a breeding site for horseshoe crabs, which are often called “living fossils” because their appearance has barely changed for about 200 million years. However, the population had plunged due to coastal reclamation and other reasons. The Envi-ronment Ministry’s Red List classifies horseshoe crabs as critically endangered.

The Kasaoka city government established the Kasaoka Horseshoe Crab Museum in 1990 and implemented ordinances that banned activities that disturbed the habitat in the breeding sites as well as setting a target of releasing 1,000 horseshoe crabs into the sea each year.

Local residents have also contributed to a rebound in the creature’s population by cleaning up the coastline. Nearby fisheries cooperatives chipped in by rescuing horseshoe crabs that got caught in nets near Kasaoka and giving them to the museum.

The annual number of live horseshoe crabs caught between fiscal 2006 and fiscal 2010 declined to the single digits, but this figure has generally trended upward despite a few dips since then.

In fiscal 2014, a large number of egg-bearing females were caught, which enabled the bumper release of 18,323 juveniles that year. According to Satoshi Morinobu, head of the museum, the hefty release in fiscal 2014 highly likely set the stage for the latest increase in their population.