Influence of environmental conditions on the ovarian cycle and serum chemistry of Cyprinus carpio in the Dal lake, Kashmir (India)

SUMMARY 1. The study presents adaptive and acclimatory changes observed in Cyprinus carpio communis L with respect to ovarian cycle and serum levels of electrolytes, calcium, total proteins and albumin as a consequence of wide temperature and sunshine variation in the natural environment of Dal lake in Srinagar, Kashmir (India).
2. The atmospheric temperatures in Srinagar show well-defined seasonal and diurnal variations. During the period of study, the mean monthly average temperature in summer (June-August) was 24°C whereas in winter (December-February) it fell to 3.6°C. The total hours of sunshine during the winter months were about half of those found in summer.
3. Under local thermal and photo conditions the fish was found to spawn once a year compared to biannual spawning in tropical chmates.
4. A significant decrease was found in serum sodium, potassium and chloride concentrations during the months of January and February when the mean minimum atmospheric temperatures reached ?2.5°C and ?l.2°C respectively.
5. The serum calcium levels showed a marked increase during the period corresponding to ovarian maturity and spawning of fish.
6. A significant rise in total serum protein concentration was induced by decreased environmental temperatures. Serum albumin levels were found to exhibit a sharp fall coinciding with the spawning period.