Diversity, Abundance and Population Structure of Shore Crabs (Decapoda: Brachyura; Menippi-dae, Eriphidae, Xanthidae, Oziidae) at Nom Sao Island, Chanthaburi Province, the Eastern Gulf of Thailand
28 ธ.ค. 2564
Research on the diversity, abundance and population structure ofshore crabs (Decapoda: Brachyuran: Menippidae, Eriphidae, Xanthidae, Oziidae) atNom Sao Island, Chanthaburi Province, was conducted for a period of aroundnine months in 2019, starting in January through to May and then continuingfrom September to December. The study area focused on four ecosystems: sandbeaches, rocky shores, coral reefs, and bare ground. Specimens were collectedvia collapsible crab traps, driftnets and free-hand methods. Species identificationwas made in both external and internal morphology consideration. The resultfound that species diversity of shore crab belonged to 4 families, 6 genera and 9species. One species of Menippidae (Myomenippe hardwickii), two species ofEriphiidae (Eriphia ferox and E. sebana), three species of Oziidae (Ozious guttatus,O. rugulosus and Epixanthus frontalis) and three species of Xanthidae (Leptodiusnigromaculatus, Atergatis integerrimus and Atergatis floridus) were found. Thehighest dominant species was L. nigromaculatus (280 individuals/square meter,53.33%). Moreover, the rocky shore was found highest diversity (9 species) withthe highest abundance of xanthid crabs. The highest abundance of nine crabswas found in April (130 individual/square meter, 24.76%), but in contrast, A.integerrimus was found the whole year. In addition, the ratio between male andfemale crab was 1:0.46. Carapace size distribution was found in the highestrange 11-20 mm. The relationship between the abundance of shore crabs andecological factors was significantly different with transparency depth (P < 0.05).