As applied to Artemia, inoculation means the introduction of the species in a suitable aquatic environment where for some reason the animal is absent.
Inoculation is done with a small number of living Artemia, either in the early nauplius - or later subadult or adult stage. When the environment is suitable in respect to salinity, temperature and food availability, the inoculated or newly introduced Artemia will thrive and reproduce. The population will grow and reach a size that can be sustained by the environment (carrying capacity).
Mostly food availability is the limiting factor for population growth. Salinity and temperature being within tolerance ranges, an increase in available food will result in a higher carrying capacity and thus in a larger population. A decrease in available food will in the same way result in a smaller population. Since in outdoor ponds the carrying capacity can not be kept constant, population will fluctuate in accordance with the carrying capacity.
In the case of Artemia, population growth is not density-restricted in unlimited conditions.
Artemia has a worldwide (cosmopolitan) distribution. As previously mentioned it occurs in all continents and consequently many different geographical strains exist. Each of these strains have in the course of time become more and more adapted to specific local conditions. For instance concerning temperature, Canadian and Indian strains differ significantly in their temperature tolerance, since they live in almost opposite climatic conditions.
It follows that an inoculation will have a better chance to succeed if a strain is selected with a habitat as identical as possible to the new site. For the Philippines this means that inoculation strains from other tropical or sub-tropical regions are favorable compared to temperate strains.
The main reason why Artemia does not occur naturally in S.E. - Asia is because of the heavy rainfall during the rainy season. During this period salinity in every closed water body is washed out and turns into freshwater. Artemia does not survive in freshwater and even if it would, invading predators such as fish, shrimp and water insects would easily eradicate the population.
In their natural finding-places Artemia can survive because it occupies a very specialized habitat, i.e. very saline water bodies where only Artemia and a few algae and bacteria species can live. Predation is therefore almost non-existent.
In S.E.-Asia highly saline waters exist only during the dry season and are mostly found in solar salt farms. In these regions, Artemia inoculation should therefore be performed in the beginning of the dry season as soon as a salinity of 100–110 ppt is reached which prevents any kind of predator. At the end of the dry season the Artemia population will die off or be eradicated completely. A new inoculation will be required in the beginning of the following dry season.
In countries with a negative yearly water balance and no distinct heavy rainy season, inoculation has only to be performed once to establish a permanent Artemia population.
