Vibrio Diversity And Dynamics In Crab (Portunus Trituberculatus) Pond

Aquaculture practices are the new innovation on sustainable development of natural resources such as fish and other shellfish. In China, gazami crab (Portunus trituberculatus) is a kind of marine crabs of economic value. However, the recurrent occurrence of disease outbreaks in aquaculture is one of the major constraints towards yielding high productions. This study aims at identification of Vibrio related bacteria, diversity and dynamics of presumably potentially aggressive Vibrio pathogens under aquaculture settings in order to assist the developing of certain measures or controls to reduce disease outbreaks.The Identification of Vibrio related isolates preceded by utilization of 16S rDNA based techniques over a period of five months. A total of 249 isolates of heterotrophic bacteria were isolated on TCBS from water, sediment and crab samples then sequenced and assigned to 4 families, 8 genera, and 43 species. Vibrionaceae (200 strains, 80.3%), Enterobacteriaceae (15 strains, 6.0%), Shewanellaceae (26 strains, 10.4%), and Staphylococcaceae (8 strains, 3.2%).Vibrio were present at all sampling times, Vibrio harveyi proved to be the most robust by being dorminant at all times and highest number of ribotypes. Other apparently potentially pathogenic strain found included V. parahaemolyticus, V. alginolyticus, V. furnissii and V. coralliilyticus. The dorminace of V. harveyi and its species-species diversity in these aquaculture ponds may rather have an important ecological role over pathenoginicity.The community structure succession of Vibrio in the pond was mainly dormininated by V. harveyi, then other species such as V. alginolyticus, V. gigantis, V. natriegens and V. rotiferianus. In crab, V. natriegens appears to be more abundant than in any other samples therefore suggesting crab is the preferable host for V. natriegens. Although there are a lot of Vibrio species, it still doesn't account for being the main pathogenic agents in pond water as their sucession varies from time to time and differs from one source to another in pond water.