New strategies are being proposed in marine aquaculture to use marine bacteria as alternative to antibiotics, as nutritional additive or as immune-stimulant. These approaches are particularly promising for larval and juvenile cultures. In many cases, the bacteria are released in the seawater, where they have to be at appropriate concentrations. In addition, only low-cost technologies are sustainable for this industry, without any complex requirements for use or storage. In this work, we explore the possibilities of preservation of a potential marine probiotic bacterium (Phaeobacter PP-154) as a product suitable for use in marine aquaculture by addition to the seawater. A method which guaranteed the preservation of the viable marine bacteria in a saline medium and their rapid release in the seawater was searched for. In a previous step, classical procedures (freeze-drying and freezing) had been explored, but undesirable results of the interaction of the products obtained with natural seawater led to investigate alternatives. We report the results of the immobilization of the marine bacteria in calcium alginate beads. The final product complies the salinity which allows the requirements of the bacteria without interference with alginate in the formation of beads, and a balanced hardness to retain the bacteria and to be easily released in the marine aquaculture environment. The process was evaluated using the central composite rotatable design (CCRD), a standard response surface methodology (RSM).