The brine shrimp, Artemia, belongs to the phylum Arthropoda (joint-legged invertebrates), class Crustacea (shrimp, crab, lobster). There are several species of Artemia worldwide; Artemia franciscana is the species living in Great Salt Lake (and also in San Francisco Bay). Brine shrimp live in hypersaline lakes in which the salt content may be 25%, predators and competitors are few, and algal production is high. The life cycle of Artemia begins from a dormant cyst that contains an embryo in a suspended state of metabolism (known as diapause). The cysts are very hardy and may remain viable for many years if kept dry. Water-temperature and salinity changes in Great Salt Lake occur in about February and cause the cysts to rehydrate and open to release the first growth stage, known as a nauplius larva. Depending on the water temperature, the larvae remain in this stage for about 12 hours, subsisting on yolk reserves before molting to the second nauplius stage, which feeds on small algal cells and detritus using hair-like structures on the antennae known as setae.