تاثير وزن بر قابليت تطابق و تنظيم يوني در بچه ماهيان آزاد درياي خزر (salmo trutta caspius)

The Effect of Size on Ion Regulation Ability in Juvenile Caspian Trout, (Salmo trutta caspius), Kessler, 1877

Determination of suitable size for releasing of the Caspian trout juveniles into the Caspian Sea to enhance its fishery return was investigated through Na+, Mg2+, Ca2+ and CI" regulation ability of 5, 10, 15 and 20 grams juvemiles in freshwater (control), the Caspian Sea water and 7 PPT water media. Blood samples were drawn at 0, 3, 6, 12, 24, 72, 168 and 240 hrs, using heparin tubes, and centrifuged to extratct the plasma. Ca2+, Mg2+ and CI" ions in the plasma were measured using RA-1000 instrument, while Na+ was estimated using Flame Photometer. The ionic fluctuations within 10 days of experimental period indicated that fish of all size groups could regulate their ions in water of 7 PPT salinity while in the Caspian Sea water the 5gram group failed to do so.