¹BINH T. DANG, ²OANH TK LE, ³SANG. Q. TRAN, ⁴OANH. TT, ⁵HENRIK GLENNER
1,3,4Institute for Biotechnology and Environment, Nha Trang University, 02 Nguyen Dinh Chieu, Nha Trang City, Vietnam
2Vietnam – Russia Tropical Center, 30 Nguyen Thien Thuat, Nha Trang City, Vietnam
5Department of Biological Science, University of Bergen Postboks 7803, N-5020 Bergen
E-mail: ¹binhdt@ntu.edu.vn

Abstract
Blue swimming crab (Portunus pelagicus) was the economic and ecological important species in Vietnam, and potential subject for aquaculture as well. More than 400 crab individuals were collected along the Vietnamese coastline, and examined for ectosymbiotic crustacean. High diversity of 7 species have been reported, and 7 probably new for science. The significant differences were detected between the infestation status of common occurring symbionts against the crab host distribution (north, cemter, and south), sexes, and size groups. Symbiotic crustacean occupied specific niche(s) on crab body. Molecular phylogeny supported the separation of 2 distinct lineages represented for two subclass (Thecostraca and Copepoda). Further studies need to be conducted for new species description.

Keywords - Symbionts, Crustacean, Portunus pelagicus, Phylogeny, Infection, Vietnam