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

Abstract

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.