Hermit crabs under threat: experts

CRAB CAMPAIGN: While a campaign in the early 2000s helped conservation efforts, a survey in 2024 found that large hermit crabs had almost disappeared from coastal forests

• By Tsai Tsung-hsien and Sam Garcia / Staff reporter, with staff writer

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The Hengchun Peninsula’s (恆春半島) coastal ecosystems are facing a severe ecological crisis, with invasive yellow crazy ants, overfishing and regulatory loopholes endangering terrestrial hermit crabs, Conservation researchers have warned.

While efforts to protect terrestrial hermit crabs saw success in the early 2000s after a public campaign to provide them with discarded shells, surveys conducted in 2024 and last year found that large hermit crabs had almost completely disappeared from coastal forests, Taiwan Academy of Ecology chairman Liu Hung-chang (劉烘昌) said last week.

Commercial catching has intensified as larger crabs command higher prices in the market, while invasive yellow crazy ants kill many land crabs and other native species for protein, Liu said.

A terrestrial hermit crab is pictured in an undated photograph.

Photo: Tsai Tsung-hsien, Taipei Times

A 2023 survey of the protected coconut crab, a giant land hermit crab, found that only one of nearly 100 crabs weighed more than 1kg, raising concerns about reproduction among the population, he said.

Protecting land crabs is essential to restoring the coast’s ecosystem as they break down fallen leaves and accelerate microbial activity in the soil, Liu said, urging people not to catch, buy or harm them.

Land hermit crabs are an evolutionary “orphan group,” as their animal family, the Coenobitidae, is the only one within the Anomura animal group that has fully adapted to life on land, Kenting National Park land crab researcher Li Jheng-jhang (李政璋) said.

They rely on the microenvironment inside their shells to retain enough moisture to survive on land, making habitat conservation a top priority, Li said.

While the coconut crab is a protected species, other common land hermit crabs that are often sold are not, marine biologist Chiu Yu-wen (邱郁文) said.

People selling them often claim they are bred in captivity, but this is not possible, Chiu said.

Current technology is unable to breed them in captivity on a commercial scale, meaning that 100 percent of the land hermit crabs sold on the market are caught in the wild, Liu said.

Authorities should first verify that any animals being sold are legally sourced under the Act on Wildlife Conservation (野生動物保育法), Chiu said.

They should also require sellers to provide the appropriate documents as required under the Regulations Covering Commercial Wildlife Raising and Breeding (營利性野生動物飼養繁殖買賣加工管理辦法), he added.

Authorities should enforce the Environmental Education Act (環境教育法) and animal welfare standards to prevent illegally collected wild animals from being passed off as legally sourced, he said.

The Kenting National Park Headquarters launched a campaign calling on people to return crabs to nature, warning that wildlife protection laws are inadequate and that greater public awareness is needed to protect the Hengchun’s Peninsula’s coastal ecosystem.

Hermit crabs are difficult to keep in captivity and their natural habitat is the best place for them to live, park headquarters director Hsu Shu-kuo (許書國) said, adding that people should learn about them through wildlife observation and environmental education rather than buying them.

While hunting wild animals within a national park is illegal under the National Park Act (國家公園法), there are disputes over what regulations apply to the sale of such animals outside national parks, Han said.

Enforcement under the Act on Wildlife Conservation is challenging because local governments have often not designated protected areas as required, leaving loopholes that illegal traders can exploit, he said.