EFFECTS OF TEMPERATURE ON THE DEVELOPMENT AND POPULATION GROWTH OF BRINE SHRIMP(ARTEMIA PARTHENOGENETICA GAHAI)
JIA Qin Xian ① XU Ning ② ZHU Jiang ① XU Mu\|Qi CAO Hong (① Institute of Zoology, The Chinese Academy of Sciences, Beijing 100080,China) (② Institute of Hydrobiology, Jinan University, Guangzhou 510632, China)
The effects of temperature on the population of the brine shrimp ( A. parthenogenetica gahai) in the Gahai Salt Lake were studied. The major results are as follows. 1) The cold tolerance (TC) test showed that the TC of the nauplii was the strongest, followed by the adult and the larve in whole lifetime. The TC of nauplii was -1 7℃ higher than that of larvae and -0 9℃ higher than that of adults. 2) The adaptive temperature for brine shrimp ranged from 11℃～38℃. The threshold temperature of development (TD) and the effective accumulative temperature (TA) for hatching were 9 94℃ and (22 91 ±2 08)℃·days, respectively. The TD and TA for the larva were 10 33℃ and (261 26±24 1)℃·days, respectively, for a whole generation were 10 28℃and (458 68±57 60)℃·days, respectively. 3) The population net reproduction rate( R o ),the intrinsic rate of natural increase ( r m ),the mean generation time ( T ),the finite rate of increase ( λ) and the days for population doubling time ( t ) of the brine shrimp were determined over a temperature range of 19 ℃～34 ℃. The results shown that the optimum temperature (℃) for R o, r m, λ and t were 25 8,29 8, 30 5 and 29 02, respectively. The maximum values of R o, r m and λ were 54 86 ind., 0 11 day -1 and 1 1 day -1 , respectively. The minimum value of \%t\% was 4 73 days. In the temperature range of 14 3℃～37 3℃, the value of \%T\% was in a range of 96 77～16 10 days. 4) Based on the data about the water temperature in the Gahai Salt Lake, Qinghai Province, which was collected from 1993 to 1994 and in 1997, it was estimated that the annual number of generation of A. parthenogenetica gahai and the annual number of the reproductive peak were 2 67±0 34 and 4 69±0 43, respectively, in a year. The peak of nauplii of first generation was from April 20 to 28 The last generation began on August 10 The first reproductive peak was from June 18 to 25 The last reproductive peak was from September 12 to 17. The nauplii hatching after September 1, could not complete the development from nauplii to adult because of insufficient habitat effective accumulative temperature. During a period from July 11 to September 20, there was a relatively high population productivity. In this case, doubling of the population would take less than 30 days, and the intrinsic rate of natural increase was over 0 02 day -1 .