Document Type : Research Paper
Authors
1
Head of Aquaculture department/ Iranian Inland waters Aquaculture institute
2
2- Iranian Fisheries Science Research Institute, Agriculture Research, Extention and Education Organization,Tehran, Iran
3
1- Inland Waters Aquaculture Research Center, Iranian Fisheries Sciences Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Bandar Anzali, Iran
4
Iranian Fisheries Science Research Institute, Agriculture Research, Extention and Education Organization,Tehran, Iran
10.22124/japb.2025.26509.1524
Abstract
In this study, Caspian kutum fingerlings with 2.5 ± 0.3 g body weight was used, which were placed in 3 groups: Caspian Sea water with a salinity of 11 ppt, water with a salinity of 7 ppt (estuary conditions), and freshwater (river conditions with a salinity of less than 0.5 ppt), and each group had three replicates. At time intervals of 0, 3, 72, and 240 h, blood was taken by cutting the Caudal Peduncle and collecting blood using heparinized capillary tubes. The concentrations of Mg++, Ca++ and Cl- ions were measured by spectrophotometry, Na+ and K+ ions by flame photometry, osmotic pressure by measuring the plasma freezing point, and the level of blood cortisol hormone based on the RIA method. Classical histology was used to prepare kidney tissue sections. From the results of ion and osmotic pressure measurements on the 10th day of the experiment, it can be confirmed that 2.5 g fingerlings can regulate their osmolarity in the salinity range of 7 (estuary conditions) to 11 ppm (Caspian Sea water). If the estuary conditions for releasing Caspian kutum fingerlings are suitable, 2.5 g fish can be used for release into the estuary to preserve the stocks. However, if the river conditions and estuary conditions for releasing the fingerlings are unfavorable, 2.5 to 3 g fish can be released directly in coastal areas (with a salinity of 11 ppt). However, if the river conditions are suitable, releasing Caspian kutum fingerlings in river areas would be a necessary condition for their gradual adaptation.
Keywords
Main Subjects
)