Species information
Scientific name: Coenobita purpureus
Japanese name: ムラサキオカヤドカリ
Chinese name: 紫陸寄居蟹
English name: Blueberry hermit crab
Origin: Southern Kyushu, Ryukyu Islands, Ogasawara Islands
Ecology and description
Coenobita purpureus occurs in southern Kyushu, the Ryukyu Islands and the Ogasawara Islands. It was long considered endemic to Japan, but it has also been found in Taiwan in recent years. Its shield length reaches about 24mm at most. Adults range in color from light blue to dark purple, and some individuals are whitish. Juveniles are cream to pale yellow and are difficult to distinguish from juveniles of other land hermit crabs.
Land hermit crabs in Japan are designated as natural monuments, and collecting them is prohibited. The bright color of adult Coenobita purpureus makes it a frequent target of poachers. Poachers have been arrested for collecting land hermit crabs on both Okinawajima and Amami Oshima, and poaching causes serious damage to land hermit crab populations.
References: 陸寄居蟹研究室 (in Chinese)
Field photographs taken during our tours, with observation dates
Related News
2026/6/25Two Chinese Men Arrested for Illegally Capturing 100-200 land hermit crabssPoachingAmami Oshima
Two Chinese men were arrested for attempting to capture 100-200 land hermit crabss without permission on a beach in Amami City, Kagoshima Prefecture. The men, aged 28 and 33, claimed they were unaware of the prohibition. A similar incident occurred last year, and police are investigating possible connections. The crabs are a national natural monument, requiring government permission for capture.
Source：FNNプライムオンライン ↗｜奄美新聞 ↗｜ｄメニューニュース ↗｜okinawatimes.co.jp ↗｜Yahoo!ニュース ↗
2026/6/24Possession of Approximately 13 kg of Land Hermit Crabs - Amami Shimbun
On June 24, Amami Police arrested two Chinese nationals for possessing 12.8 kg of land hermit crabs, a national natural monument, without permission. Most of the seized crabs are believed to be Blueberry Hermit Crabs, likely intended for illegal sale. The suspects were found in a rental car with bags full of crabs after a local report. The crabs have been moved to a protection facility and will be kept as evidence until a verdict is reached. The Amami mayor plans to strengthen preventive measures.
Source：amamishimbun.co.jp ↗
2026/2/3Scratching sounds from suitcase reveal large number of land hermit crabs... Poaching of rare species by Chinese group on Amami OshimaPoachingAmami Oshima
Poaching of rare species is on the rise in the Ryukyu Islands. Since last spring, a Chinese group was arrested on Amami Oshima for illegally capturing over 5,000 land hermit crabs in about a week. In Okinawa, foreign nationals were caught capturing endangered Okinawa black-breasted leaf turtles. These species are highly valued in overseas markets, prompting experts to call for stricter penalties. In May, suspicious suitcases containing about 5,200 land hermit crabs were found at a hotel on Amami Oshima, leading to the arrest of three Chinese nationals. Land hermit crabs are designated as national natural monuments and their export is prohibited.
2025/5/29Amami Hermit Crab Capture Incident: Three Chinese Nationals Caught for 'Sales Purpose' Worth Over 100 Million Yen? Hotel and Conservation Group Receive Commendation in Kagoshima
Three Chinese nationals were fined 300,000 yen for illegally capturing 5,200 land hermit crabs, a national natural monument, on Amami Oshima. They admitted to capturing them for sale, potentially worth over 100 million yen. On May 29, commendations were given to the hotel and conservation groups that reported the incident. The crabs will be released back to five coastal areas where they were captured.
Source：TBS NEWS DIG ↗｜南海日日新聞 ↗
2025/5/235,200 National Natural Monument Land Hermit Crabs 'Captured Over a Week on Amami Oshima'... Three Chinese Nationals Suspected of Unauthorized Possession
Three Chinese nationals were arrested for possessing approximately 5,200 land hermit crabs, a national natural monument, without permission. They reportedly captured the crabs over a week on Amami Oshima, possibly for resale. The crabs, weighing 160 kg, were brought to Amami by air from Kansai International Airport in late April. About 130 crabs have died, and the remaining are stored in tanks. Authorities are considering whether to return them to the wild.
Source：読売新聞 ↗
2026/9/11Three Chinese Men Fined for Capturing land hermit crabss, Okinawa Summary CourtPoachingOkinawa Island (other)
Three Chinese men in their 20s were fined 400,000 yen each by the Okinawa Summary Court for illegally capturing and moving around 6,000 land hermit crabss, a national natural monument, in Okinawa from June to July. They were arrested in August for capturing 4,163 crabs in June and 2,207 in July without permission, intending to sell them. The Naha District Public Prosecutors Office filed a summary indictment in September.
Source：琉球新報デジタル ↗｜TBS NEWS DIG ↗｜Yahoo!ニュース ↗
2026/8/11[Overharvesting] Targeted Natural Monument: Three Chinese Nationals Repeatedly Poaching 'land hermit crabs', Re-arrested. Illegal Capture Totals 2 Cases, 6370 Crabs... How Can We Detect Poaching?
In Okinawa, three Chinese nationals have been re-arrested for allegedly repeatedly poaching the land hermit crabs, a designated natural monument. They are accused of illegally capturing a total of 6,370 crabs in two incidents. The rarity of the land hermit crabs makes it a target for poaching. This incident is part of a series of poaching activities, and the public is urged to be aware of poaching methods and signs.
2026/7/4"Even the small ones were uprooted..." 3869 land hermit crabss Poached, Four Vietnamese Fined 300,000-400,000 Yen in OkinawaPoachingOkinawa Island (other)
By July 3, four Vietnamese nationals were summarily indicted by the Naha District Prosecutor's Office for illegally capturing and transporting 3,869 land hermit crabss, a national natural monument, in Okinawa. The Naha Summary Court fined two men 400,000 yen each and two women 300,000 yen each. The incident was uncovered after a delivery company noticed something unusual and reported it to the police. The Okinawa Prefectural Board of Education urges cooperation to prevent poaching and advises the public to report suspicious activities.
Source：Yahoo!ニュース ↗
2025/7/12[With Video] Suspected Poaching of Land Hermit Crabs, Man Arrested by Ginowan Police, Over 2,500 Seized in OkinawaPoachingOkinawa Island (other)
A man was arrested by Ginowan Police for suspected poaching of land hermit crabs, with over 2,500 seized in Okinawa. Details are not available.
Source：琉球新報デジタル ↗
2025/6/13Call for Voluntary Ban on Taking Wildlife from Amami Oshima and Tokunoshima: Local Governments Release Joint StatementPoachingAmami OshimaTokunoshima
Amami Oshima and Tokunoshima in the Ryukyu Islands are home to unique wildlife, but these species are often taken off the islands for pet trade and sale. Local governments have issued a joint statement, "Request from the Islands," to curb this practice, although it lacks legal force. In May 2025, 998 land hermit crabs were prevented from being taken off the islands. WWF Japan continues to support local conservation efforts.
Source：WWFジャパン ↗