Adaptation Of The Brine Shrimp Artemia Sauna (Branchiopoda: Anostraca) To Filter-Feeding: Effects Of Body Size And Temperature On Filtration And Respiration Rates

In spite of wide use of the brine shrimp, Anemia sauna (Linnaeus, 1758), as feed and model organism in evolutionary, ecological, physiological, and ecotoxicological investigations, only a few studies have attempted to quantify filtration and respiration rates in order to characterize A. sauna as a filter-feeder. Herein, we measured that the maximum filtration rate (F, ml/h) as a function of body length (L, mm) can be expressed by means of two equations, one that applies for small (<2.5 mm) individuals: F = 0.858L - 0.8539, and one for larger juvenile and adult animals: F = 1.6376L - 3.297. An increase from 15 to 25 degrees C resulted in an increase of the filtration rate with a factor of 1.53 +/- 0.19, and likewise, a decrease from 30 to 20 degrees C resulted in a decrease of the filtration rate with a factor of 2.16 +/- 0.55. The respiration rate (R, mu g O-2/l) as a function of body length measured on starved A. sauna at 15 and 25 degrees C increases with body length according to R-25 degrees C = 1.149e(0.528L) and R-15 degrees C = 1.243e(364L), respectively. The estimated FIR-ratio, which can be used to characterize A. sauna as a filter-feeder, was found to be 7.4 and 6.61 H2O/ml O-2 at 25 and 15 degrees C, respectively. The relatively low ratios indicate that the animal, which lives in salt lakes, is not well adapted to nourish itself in typical marine areas and is unfit to compete for food with the more advanced copepods and other filter-feeding crustaceans in the sea.