Least Concern· population stable· assessed 2008

Japanese Freshwater Crab

Geothelphusa dehaani

Sighting evidence at Izu Oceanic Park, Izu Peninsula

Evidence at this site

25 records within 25 km

Confidence: medium

Last confirmed Jun 2026

Seasonality

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

How is this calculated?

Sighting evidence is compiled from iNaturalist observation records within a set proximity radius, filtered for quality-grade observations. “Last confirmed” is the date of the most recent research-grade record. Record count covers a rolling 24-month window. Confidence reflects record count, recency, and consistency of seasonal signal.