Revisiting the methods of Artemia reproductive performance test (Anostraca: Crustacea)

Artemia cf. parthenogenetica Bowen and Sterling, 1978 is widely distributed in the saline lakes of Northern Kazakhstan. Female Artemia can easily be recognized by a brood pouch full of cysts before being released. The number of cysts can be used to estimate both individual reproductive performance and the entire population. During the studies involving Artemia reproductive performance, it was observed that throughout the growing season, in the water bodies, there were females whose well-developed brood pouches were partially filled with cysts. Thus, we were confronted with a question about the relevance of using females with partially filled brood pouches to determine the reproductive performance of Artemia. The number of cysts in a full brood pouch and a partially filled brood pouch revealed consistent differences in the following statistical indicators: average reproductive performance, coefficient of variation, and average minimum and maximum reproductive performance. As the percentage of females in the population with cysts not yet ready to be released increases, the percentage of females with partially filled brood pouches decreases. The general conclusion is that the use of females with partially filled brood pouches underestimates the valid value of average reproductive performance and also changes the pattern of the reproductive performance distribution. The obtained results prove that only females with a full brood pouch should be used when assessing the reproductive performance value of Artemia.