The Cham Islands belong administratively to Hoi An city, Quang Nam province, and is a marine protected area (MPA) with great environmental and marine diversity. The island’s rich biodiversity includes a species of large crab locally named “Cua Da” (Gecarcoidea lalandii) of the Cham Island. While G.lalandii is a species associated with marine fauna, individuals mainly occur in terrestrial forests and when carrying eggs, females migrate to the coast where they release the eggs in coastal hollows during their breeding season. The Cham Island’s G.lalandii is considered a “bridge” connecting terrestrial forests with the marine environment and is a biological indicator of the health of terrestrial and marine ecosystems. This is one of the important resources closely associated with local people’s lives as it significantly contributes to their livelihoods. Unfortunately, the Cham Island’s G.lalandii is prone to be severely depleted due to overharvests and a substantial increase in tourists to the island.