Combined effects of salinity and temperature on survival and reproduction of five species of Artemia

Abstract

Abstract Survival and reproductive performance were measured at nine temperature–salinity (T–S) combinations (15°C, 24°C and 30°C/60 ppt, 120 ppt and 180 ppt) for four sexual ( Artemia franciscana , A. salina , A. sinica and A. persimilis ) and one parthenogenetic ( A. parthenogenetica ) species of brine shrimp. There was significant interaction between temperature and salinity for survival and reproductive traits. For most species there was disconcordance among seven performance estimators (LT 50 , 21-day survival, r , and four female reproductive traits) for the optimal T–S combination. We propose that the best ecological estimator of reproductive success is cohort reproductive output because it incorporates both survival ( l x ) and reproductive ( m x ) functions. All species had maximum reproduction at 24°C; at 120 ppt for A. parthenogenetica , A. sinica and A. franciscana , and at 180 ppt for A. salina and A. persimilis . There was only one T–S combination (24°C/120 ppt) where all species completed their life cycle. While at least one Artemia species reproduced at eight of the nine possible T–S combinations, sustainable reproduction (where R o ≥1) occurred at only five T–S combinations. A. parthenogenetica had the narrowest tolerance range of T–S combinations, contradicting the general purpose genotype hypothesis advanced for obligately parthenogenetic species.