Examining population-specific hatching cues of salinity and light for Artemia franciscana

Dormancy, the physiological start of rest, occurs in numerous animal species. Many crustaceans release various types of encased embryos in a state of dormancy (e.g., cysts, ephippia, etc.). These dormant propagules require specific combinations of abiotic environmental cues to terminate dormancy. Our goal was to determine if population-specific responses to varying levels of salinity and light (photoperiod) would be present in dormancy termination of the brine shrimp, Artemia franciscana, from distinct environments. Therefore, we cross-factored different salinity concentrations and photoperiods with three A. franciscana populations collected from geographically distinct environments. To measure population-specific response, hatching success (i.e., hatching percentage) was calculated for each treatment. Our results supported the hypothesis that diverse populations of A. franciscana do have population-specific responses to photoperiod and salinity ranges, which affect hatching success (e.g., a population from Portugal showed the greatest hatching success at a salinity of 50 g/l, while populations from Spain and the U.S.A. exhibited the greatest hatching success at 25 g/l). These population-level differences should be taken into consideration during experimentation, especially when examining hatching success in this model organism.