[Thermal and salinity tolerance of eurybiotic freshwater shrimp Gmelinoides fasciatus (Stebbing) under different acclimation conditions].

Critical thermal maximum and critical salinity maximum in their dependence on the water temperature and salinity were studied in the freshwater shrimps, Gmelinoides fasciatus, during their acclimation. Nine combinations of temperature (12.7-14.7, 16.3-21.3, 22.0-25.6 degrees C) and salinity (0.2, 2.5 per thousand) were studied. The shrimps were shown to be largest CTM in the fresh water at 22-26 degrees C and to be smallest CTM at 12-14 degrees C. The thermal effect on the thermal stability was similar in the brackish water (2 per thousand), while its effect on the salinity stability was reverse, that is, the shrimps' endurance to the high salinity decreased with the temperature growth. During acclimation, viability reached 50 to 100 per cent at 5 per thousand, the individuals adapted to the lower temperature (12-14 degrees C) appearing to be most endurant. Thermal stability was revealed to increase with the body length growth reaching the stable level at the body length of 7-8 mm. Salinity stability of the shrimps acclimated in the brackish water at 22-26 degrees C tend to increase with the body length growth, while it did not depend on the body length at other temperature regimes reaching about the same level in both fresh and brackish waters. The data obtained indicate that the temperature below 22 degrees C would be optimal for the shrimps acclimation in the brackish water.