An alternative outdoor production system for the microalgae Chaetoceros muelleri and Dunaliella sp. during winter and spring in Northwest Mexico

Shrimp hatcheries have faced problems related to microalgae production: a wide variability on final densities, and marked differences in nutritional composition. An alternative system for the outdoor culture of Chaetoceros muelleri and Dunaliella sp. during winter and spring in Northwest Mexico was evaluated. The new system increases the exposure of microalgae to light by introducing a recirculation cascade. Higher growth rates and final densities of both species were found in the alternative system independently of the season. In the winter trial, cell density of C. muelleri at 92h was 0.85×10⁶cellsmL^-1 in the alternative system, compared to 0.57×10⁶cellsmL^-1 in the traditional. Dunaliella sp. reached a density of 0.26×10⁶ and 0.23×10⁶cellsmL^-1in the alternative and traditional systems, respectively. In spring, density of C. muelleri in the alternative system was 2.8×10⁶cellsmL^-1, in the traditional 2.08×10⁶cellsmL^-1. For Dunaliella sp. 0.83×10⁶ and 0.78×10⁶cellsmL^-1 were respectively obtained. No differences in dry matter biomass were observed among systems in any trial for the two species. We concluded that the alternative system is a good option to improve the production of microalgae especially during spring. Better results were achieved for C. muelleri.