Development of a closed-recirculating, continuous culture system for microalga (Tetraselmis suecica) and rotifer (Brachionus plicatilis) production

摘要

We have designed, built and operated a closed-recirculating, continuous culture system to produce microalgae and rotifers in seawater (25% salinity) for larval fish culture. The system opens a new perspective in terms of automated production of rotifers without labour cost. Rotifers can be easily harvested daily by a conical harvest net and there is no routine maintenance work. This new, automated system has three components: a microalga culture, a rotifer culture and storage with harvest, and a water treatment and re-use component. After treatment using mechanical filtration, biofiltration, UV sterilization, ozonation, and protein skimmers, water is re-used, thus nearly eliminating the need for seawater imports to the system. Our trial demonstrated that this culture system is capable of producing sustained and acceptable levels of rotifer production for at least 28 days. Microalga densities and yields were quite stable, while rotifer yield varied more during our 28 day culture period. Nitrogenous waste compounds were stable and well within acceptable levels, although nitrate and phosphate concentrations increased throughout the culture period, but did not negatively impact on rotifer production.