Akademik Veri Yönetim Sistemi
FISH PHYSIOLOGY AND BIOCHEMISTRY, cilt.51, sa.1, ss.1-13, 2025 (SCI-Expanded)
The negative effects of global warming also
directly affect aquatic populations. Consequences such
as evaporation due to chronic temperature increase,
increase in salinity, and increase in stock density per
unit volume are potential stress factors. While creating
the trial design, an attempt was made to simulate the
effects of global warming, especially on species liv-
ing in salty and brackish water biotopes. In this study,
changes in the gills of rainbow trout (Oncorhynchus
mykiss) acclimated to 0, 20, and 38 ‰ of saline in the
laboratory were examined histologically and immuno-
histochemically and blood serum osmolarity. In addi-
tion, the water temperature was changed, and experi-
ments were carried out at 16, 19, and 22 °C for each
salinity group in parallel with the increase in salinity.
However, to simulate the decrease in water volume and
intensive stocking due to the potential impact of cli-
mate change, the study was carried out using 15 fishes
in low-volume aquariums (45 L). Tap water that had
been kept for at least 3 days was used in the aquariums.
To protect the water quality, independent aquariums
with sponge filters were used, and since the aim was to
keep dissolved oxygen low, no ventilation system other
than the sponge filter was used. In order to minimize
the deterioration in water quality during the trial, a
15% water change was performed by performing a bot-
tom flush every 4 days and water of the same tempera-
ture and salinity was added as much as the reduced vol-
ume. In addition, since increasing stock density due to
temperature increase and water decrease will cause the
amount of dissolved oxygen to decrease, pure oxygen
was not entered into any tank throughout the experi-
ment, and the concentration was requested to be at a
low level (7 ± 0.13 mg/L) in all groups. The trials were
terminated at the end of the 71st day. Increased serum
osmolarity values were observed due to the increase in
salinity, and the highest serum osmolarity value was
measured at 644 mOsm/kg in the 38 ‰ salinity group.
Differences between the groups were found to be sta-
tistically significant (p < 0.05). It was observed that the
number of cells containing Na+/K+-ATPase increased
depending on salinity. Also, the number of chloride
cells reached the maximum level in the 38 ‰ salin-
ity group. Due to increasing salt levels, an increase
in mucus cells, limited onset hyperplasia, aneurysm,
lamellar separation, and necrosis were observed in the
gill tissue.