Physiological changes in blood and seminal plasma during the spawning period of maturing rainbow trout held under different temperature and salinity regimes, and the effect on survival of the broodstock and the eyed eggs

摘要

Maturing rainbow trouts reared in sea cages were transferred totanks and kept under nine different temperature and salinity regimes.Blood and seminal fluids were regularly sampled from the fish,and different organic and inorganic components were measured. Thesurvivel of both the broodstock and the eyed eggs were recorded.Dry matter of the eggs were measured as well.Sexual differences were noted according to the progressive changesof glucose, chloride, haematocrit and the survivel of the broodstock.Cold temperatures delayed the sexual maturation independentof salinity, and only few females spawned at these temperatures.The broodstock reared at cold temperatures in freshwater and seawater suffered from high mortality and high levels of blood chlorideor blood glucose. Brackish water appeared to be the mostfavourable environment, especially for the broodstock reared at thewarmer temperatures. The survivel of the broodstock and also ofeggs from females stripped at this salinity was high. Analysis ofthe physiological components were more stable compared to fish rearedat the other salinities.