Microbial composition in biofloc-based shrimp aquaculture systems


Shrimp disease outbreaks such as EMS can occur at the early post-stocking stage due to the presence of opportunistic pathogenic bacteria, such as species of Vibrio. EMS can cause up to 100% shrimp mortality and result in a 70% drop in total shrimp production. This bacteria-caused disease has led to the conclusion that sustainable shrimp aquaculture will depend on the development of bio-secure production systems, which need to be improved to ensure growth and disease resistance and facilitate bio-shrimp productivity towards sustainable aquaculture.

This research work focused on improving the existing methods of disease prevention by examining the nature of shrimp-pathogen interactions to identify promising applications for shrimp farming, such as the use of bio-inoculants. To successfully use microbial composition in shrimp disease management, four different approaches to intensive shrimp aquaculture were compared with regard to the bacterial composition vs. biological and operational parameters. The results indicate that the total suspended solids (TSS) and pH are the most important indicating a system’s biosecurity (i.e. indicate the stability of parameters in a system).

Overall, this thesis provides baseline information on bacterial ecology, intending to establish healthy super-intensive shrimp aquaculture with recommendations for best practices. As a future outlook, a shrimp eco-culture system is proposed with a high potential for contributing to responsible aquaculture. We propose a rapid beneficial bacteria kit, such as for Ruegeria sq1 and Pseudoalteromonas sq91 bacteria as r-matured bacteria, using biofloc technology as an alternative approach to controlling shrimp disease outbreaks via bacterial activity management.