Habitat of 30,000+ endangered white-clawed fiddler crabs found on Daebudo tidal flat
In short
The Gyeonggi Province Marine and Fisheries Resources Research Institute said on 20 October that it found two new habitats of the white-clawed fiddler crab (흰발농게) on the Daebudo tidal flat in Ansan, covering about 2,600 square metres. Density analysis put the population at no fewer than 30,000. The institute and Ansan city plan protective measures such as information signs.
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The Gyeonggi Province Marine and Fisheries Resources Research Institute said on 20 October that it had confirmed habitat of the white-clawed fiddler crab (흰발농게) on the Daebudo tidal flat in Ansan. The species is listed as Class II endangered wildlife and as a marine protected species. [ 1 , 2 , 3 ]
The habitat was found during the institute's Gyeonggi tidal flat ecological survey, which has run since June, at a site with no previous record of the species. There are two habitats, of about 1,600 and 1,000 square metres, about 2,600 square metres in all. The institute's density analysis estimated that at least 30,000 crabs live there. [ 1 , 2 , 3 ]
According to Seoul Economic Daily and Yonhap, the institute obtained permits from the Ministry of Environment and the Ministry of Oceans and Fisheries to collect a minimum number of specimens. It then confirmed through examination of morphological features and DNA analysis that they were white-clawed fiddler crabs. [ 2 , 3 ]
Egg-bearing females and young crabs were also found. The institute said this shows the crabs are not appearing at the site temporarily but are breeding and maintaining a population there. [ 1 , 2 , 3 ]
The white-clawed fiddler crab is a small crab that lives in the upper intertidal zone, the part of the tidal flat closest to land. The male has one claw that is unusually large for its body and white. Hankook Ilbo and Seoul Economic Daily wrote that habitat loss and development have cut its numbers, so it needs protection. [ 1 , 2 , 3 ]
The institute and Ansan city plan protective measures such as information signs, Hankook Ilbo and Seoul Economic Daily reported. Seoul Economic Daily added that they will also review management so that people's access and use of the tidal flat do not damage the habitat. The survey also found a small habitat of another marine protected species, balkongge (발콩게). The institute had also identified habitats of that species in the province in 2022 and 2023, the two outlets reported. [ 1 , 2 ]
Institute head Kim Seong-gon (김성곤) said the discovery shows that Gyeonggi tidal flats are an ecological space that holds biodiversity. He said the institute would work with Ansan city to keep observing the habitat and changes in the population. [ 1 , 2 , 3 ]
Why it matters
The institute said the find of egg-bearing females and juveniles shows the species is breeding and sustaining a population at the site, not appearing temporarily. Two outlets describe the species as needing protection because habitat loss and development have cut its numbers. Protective steps are planned, according to the institute and the city.
Key facts
- The Gyeonggi Province Marine and Fisheries Resources Research Institute announced on 20 October that it had found white-clawed fiddler crab habitat on the Daebudo tidal flat in Ansan. [ 1 , 2 , 3 ]
- The species is listed as Class II endangered wildlife and as a marine protected species. [ 1 , 2 , 3 ]
- The two habitats measure about 1,600 and 1,000 square metres, about 2,600 square metres in total, at a site with no previous record of the species. [ 1 , 2 , 3 ]
- Density analysis estimated at least 30,000 crabs live there. [ 1 , 2 , 3 ]
- Egg-bearing females and young crabs were also found. [ 1 , 2 , 3 ]
- The finding came from the institute's Gyeonggi tidal flat ecological survey, under way since June. [ 1 , 2 , 3 ]
- A small habitat of another marine protected species, balkongge (발콩게), was also found during the survey. [ 1 , 2 ]
Confirmed by several sources
- The institute reported two new white-clawed fiddler crab habitats of about 1,600 and 1,000 square metres on the Daebudo tidal flat, with an estimated population of at least 30,000. [ 1 , 2 , 3 ]
- Egg-bearing females and juveniles were found, which the institute took as evidence that the crabs are breeding and maintaining a population there. [ 1 , 2 , 3 ]
- The institute used permits from the Ministry of Environment and the Ministry of Oceans and Fisheries to collect a minimum number of specimens, and confirmed the species through morphological examination and DNA analysis. [ 2 , 3 ]
Still unclear
- What protective measures will be taken beyond information signs. Two outlets say the institute and Ansan city plan information signs; only one adds that management to keep people and tidal flat use from damaging the habitat will be reviewed. No details or dates are given.