Coconut Crab - World's Biggest Land Crab @ 3' - Vanishing From Indonesian Islands

[hatrack]

Coconut crabs, known in Indonesia as ketam kenari, are the world’s largest land crab. They’re also quite an unusual species: these invertebrates can live up to 60 years and measure a meter long (3 feet) from leg to leg, with claw strength 10 times greater than a human’s grip. While most photographs of these crabs show them during the day, coconut crabs are actually nocturnal, and despite their name, they don’t solely eat coconuts — although they’re capable of ripping them apart with their impressive claws.

Coconut crabs (Birgus latro) are widespread across the Pacific and Indian oceans, including in Indonesia, which straddles both. But a newly published conservation assessment finds they’re also edging closer to extinction. The species’ conservation status is now listed as “vulnerable” by the IUCN, the global conservation authority. “We were getting reports of coconut crab populations either declining or being extirpated from areas,” said assessment co-author Neil Cumberlidge, chair of the Freshwater Crustacean Specialist Group at the IUCN and professor of biology at Northern Michigan University. “This was coming initially from the Pacific, but other people were chiming in and saying, ‘Yeah, I’ve noticed it where I am … in eastern Indonesia.’”


Coconut crabs are the world’s largest land crab and are widespread across the Pacific and Indian oceans. Image by Darwin Initiative via Flickr (CC BY-NC-SA 2.0).

EDIT

Habitat destruction for coastal development and agriculture is dangerous for coconut crabs. They prefer to live in rocky shores and rainforests close to the coast. When those disappear, coconut crabs have nowhere to go. “A lot of land crabs are like that,” said Victoria Watson-Zink, a doctoral student in population biology at the University of California, Davis, and a co-author of the IUCN assessment. “Once they are in their terrestrial phase, they don’t use their gills really … to respire. So if you put them back in the water they drown, because they use a different membrane to breathe.” “The coconut crab is one of the crabs that does that. It’s really interesting, because you have this life stage that is in the ocean, but then there’s a transition that happens, and then they move onto land.”


Coconut crabs prefer to live in rocky shores and rainforests close to the coast. Image by David Stanley via Flickr (CC BY 2.0).

EDIT

While the new IUCN assessment is important for raising awareness about the plight of coconut crabs, Indonesian conservationists have been on the case for a while. Meidiarti Kasmidi, who coordinates sustainable tourism and alternative livelihood initiatives in West Papua province for Conservation International, the global environmental NGO, is one of them. Kasmidi works directly with island communities and the provincial government’s conservation agency, known by its Indonesian acronym BKSDA, on programs to survey and protect coconut crabs. According to Kasmidi, some people in the Raja Ampat archipelago continue to harvest and sell these crabs despite the fact that the animal is protected under Indonesian law. In 2019, the coconut crab population on Raja Ampat’s Fam Islands numbered 12,000 individuals, according to Conservation International, but people are catching about 3,200 per year — meaning the crabs could disappear from the islands within just four years without conservation management.

EDIT

https://news.mongabay.com/2022/02/a-bigger-deal-than-it-sounds-coconut-crabs-are-vanishing-island-by-island/