Aerobic bacterial flora in the digestive tracts of freshwater shrimp Palaemon paucidens acclimated with seawater

The changes of aerobic bacterial flora in the digestive tracts of a euryhaline freshwater shrimp Palaemon paucidens with its gradual acclimation to seawater were investigated. In the rearing water with tap to 50% seawater, microflora, both in the digestive contents and rearing water, was varied, and Pseudomonas, Vibrio-Aeromonas, Acinetobacter, Moraxella and Enterobacteriaceae predominated. In 100% seawater, however, Enterobacteriaceae dominated in the digestive contents and Pseudomonas in the rearing water. When shrimps were returned to tap water, the microflora of the digestive contents and rearing water was similar to those in the original tap water animals.