The main goal of project CRASSOREAB is to contribute to the sustainable development of Portuguese oyster Crassostrea angulata (Lamarck, 1819) aquaculture, thus rehabilitating an activity with major importance for social and economic development, both at local and global level. The project will address aquaculture challenges through the optimization of the production of the Portuguese oyster, using new strains of autochthonous microalgae with high nutritious value.
Water samples were collected from two estuaries, where wild populations of Portuguese oyster occur (SW coast of Portugal), for characterization of phytoplankton communities. From these assemblages, different microalgae species were isolated and uni-algal cultures were established for further biochemical characterization and scale-up.
Identification of cultured strains was carried out, through morphological analyses by SEM (scanning electron microscope) and molecular analyses. So far, 4 species were identified, and one is under investigation: the diatoms Thalassiossira eccentrica, Skeletonema marinoi and another centric diatom (incertae sedis) and the haptophyte Emiliania huxleyi.
These strains were successfully grown in laboratory conditions at the Algae Culture Collection of the University of Lisbon (ALISU). They were further scaled up at the Experimental Mollusc culture Station (EEMT, IPMA) and harvested at late exponential phase of the growth curve, for use as food in oyster larval rearing protocols. These cultures were also harvested and processed for fatty acid and sterol analyses. So far, in terms of fatty acid profile, including the essential HUFA (Highly Unsaturated Fatty Acids) DHA and EPA, these microalgae revealed to be of interest for the oyster aquaculture production.
The following steps will be, to use these cultures as food for other life-cycle stages, such as post-larvae and juveniles, and for the conditioning of C. angulata broodstock. The quality, viability and performance of the obtained gametes, larvae and juveniles will also be evaluated.