Cysts must be harvested regularly from the pond. Several dehydration -hydration-dehydration cycles, which happen when the cysts are left for a long time in the water and floated ashore, will decrease cyst viability and consequently cyst quality. In practice they should be harvested every time a patch of cysts has gathered in a corner and in a good Artemia pond this might be daily. Further processing of the cysts can be done once a large amount has been collected. In the meantime the cysts must be stored in a brine container (see practical work sheets).
Floating cysts will gather in a corner of the pond by wind action. From there they can be easily scooped out with a fine-meshed screen. Make sure the slopes of the dikes in all corners of the pond are steep. This will prevent the cysts from clinging to the soil. Eventually, corners can be lined with plastic sheet to obtain very clean harvests. If floating lab-lab is present, wide-meshed barriers can be placed in the water to keep the corners clean.
Also a part of the Artemia population can be harvested from the pond. Adult Artemia can be used as live food for nearby fish and shrimp nursery ponds.
The processing of the cysts is of crucial importance with regard to the quality of the product. Not only have the cysts to be dehydrated to a sufficient low level, but the quality of the product is also determined by the effective removal of dirt from the cysts. Although many different procedures exist, they all go through the following three steps: cleaning, dehydration, packaging.
The recommended procedure described in the practical work sheets is based on the bi-phase floatation principle: fractions are separated in solutions with different specific gravity.
Previous inoculation trials in Thailand and the Philippines indicate a production potential ranging between 25–55 kg cysts/ha/5 months dry season, depending on the use of extensive culture techniques with only mangrove water intake as food source or intensive techniques with fertilization.
These figures are conservative estimates and production can be probably much higher depending on the initiative of the farmer. Nonetheless they already compare favourable with production data of natural Artemia populations which average at 20 kg cysts/ha/4 months.
The processed cyst product should be checked for its quality. Quality control is easily performed by routine determination of hatching efficiency (HE) and/or hatching percentage (HP). They do not however represent the same thing. Procedures are described in the practical work sheets.
In the past most cyst distributors used HP as quality criterium i.e., the percentage of cysts that will hatch. This can be very misleading since a commercial product may contain not only cysts but also dirt in the form of sand and detritus, and this is not accounted for in the HP criterium.
As Artemia is sold on a weight basis, a much more realistic criterium is therefore the number of live naupliae the customer will get from a certain quantity of product purchased (HE). The following figures clearly demonstrate the difference between HE and HP and the possibly misleading character of the latter:
| (HP) Hatching percentage (%) | (HE) Hatching efficiency (g) | |
| Brand 1 | 82 | 17 |
| Brand 2 | 87 | 4.5 |
According to the HP the brands have more or less the same quality, but the HE indicates that brand 2 is much better than brand 1.
It is therefore recommended to use HE instead of HP as quality criterium, if the necessary equipment is available.
