Effects of temperature and oxygen tension on oxygen consumption rates of nauplii of different Artemia strains

Effects of temperature and Po2 have been examined on rates of oxygen consumption ( a o 2 ) of nauplii of 5 difterents Artemia strains acclimated to 30 %OS. In 4 strains there were no significant differences in relations between Pho2 and temperature over the temperature ranges offered (15 to 35 "C). In 1 strain (Delta del Ebro), the temperature effect on h?02 was much lower than in the other strains. Nauplii of all strains were able to maintain respiratory independence under hypoxic conditions down to a Pc of 30 to 40 Torr (15 to 20 ' C ) . The ability of the nauplii to maintain respiratory independence was reduced at higher temperatures. Nauplii from each of the strains were able to tolerate temperatures of up to 35 "C; at high temperatures Qlo values for Pho2 for 3 strains decreased; this may indicate that these nauplii were thermally stressed. Differences in temperature effects on metabolic rates of nauplii of the 5 strains are discussed in relation to the competitive abilities of the strains in their natural habitat.