The following management scheme should be followed in principle: (Fig. 2)
PREPARATORY PHASE
fill pond with high salinity water and if necessary let further evaporate.
the pond is ready once 100 – 110 ppt salinity with 30 – 40 cm waterdepth is reached and no more predators are present.
fertilize if not enough food is present in the water i.e., turbidity more than 40 cm. (see practical work sheets)
INOCULATE
GROW OUT
keep salinity within the 110–120 ppt range by regular water intake (see practical work sheets) to let grow the inoculated Artemia to the adult size.
OVOVIVIPAROUS PHASE
still maintain 110 – 120 ppt salinity range after Artemia have grown adult to let population increase through ovoviviparous reproduction. On their turn first generation naupliae will also grow adult. Population should reach a density of 40 or more individuals (adults plus naupliae) per liter.
SALINITY INCREASE
let salinity go up to 150 ppt through evaporation, but always maintain sufficient waterdepth.
OVIPAROUS PHASE
maintain the 150 ppt level by regularly taking in water. The higher salinity will induce oviparous reproduction and thus a large part of the population will start producing cysts.
keep this going as long as the weather allows it, to keep harvesting cysts.
The regular water intakes have three purposes: (1) to not let salinity go up too high. Salinities higher than 150 – 160 ppt are not necessary for good cyst production and might endanger survival through oxygen depletion. (2) To maintain sufficient waterdepth to prevent too high water temperatures. (3) To take in new food in the form of algae and organic detritus particles.
Regular observations of waterdepth and maximum daily water temperature (2–3 PM) should be carried out. Waterdepth should at all times not be less than 30 cm and water temperature should be lower than 38°C.
If the water taken in has a low food content (clean, not green water), it is necessary to fertilize in one of the following manners:
inorganic: 50 kg 16–20–0 and 50 kg 33–0–0 per ha once a week (see practical work sheets).
organic: 0.5 ton chicken manure once a week.
These fertilization rates depend on local conditions and can be decreased as long as a sufficient high food level is maintained in the water.
The above described management scheme is theoretical in nature and is merely meant as a guideline. Many things can happen such as:
Unexpected rainfall decreasing salinity. A short shower will not affect salinity too much. The danger lies in the formation of a freshwater layer on top of the highly saline pond water. This will heat up the water. There is no problem if after a shower the wind mixes the water layers.
No real control on the amount of water taken in, resulting in strong salinity fluctuations. As long as salinity is kept within a 110 – 160 ppt range this should not be a problem.
Incapability of taking in water regularly, resulting in too shallow waterdepth. This is the worst that can happen and must be prevented at all times.
Fig. 2. THEORETICAL MANAGEMENT OF ARTEMIA POND
