Abstract Mangrove area in the Nagari Gasan Gadang has been damage due to human activities and the damage negatively affects crabs living in that area. A research aims to understand species and density of crabs was conducted in December 2019-January 2020. There were 3 stations with 3 plots/station and 5 sub plots/plot. Samplings were conducted 3 times at 2 week intervals. Crabs were caught …