اثرات زمان مهاجرت توليدمثلي روي برخي خصوصيات زيست شناختي تخمك و تخم ماهي كپور وحشي (Cyprinus carpio Linnaeus، 1758) در گرگان رود

Efects of reprodactive migration time on some biological characters of eggs in Gorgan river wild common carp (Cyprinus carpio)

A survey has been done to determine some biological characterictics of eggs (including diameter, surface, volume, surface to volume) and hydrated egg (including diameter, surface, volume, surface to volume, yolk sphere, pervitel1ine space and yolk sphere to pervitel1ine space) in 90 migratory population ofwild common carp at 3 treatment (initial, middle and end of brood stock migratione time) in 2005 to 2006. Rang of egg diameter and its surface to volume were 1.2mm to 1.75mm and in hydrated eggs were 1.55mm to 2.15mm which was significant (P<0.05) at broodstock migration times and was minimum at the end of migration time and was maximum at initial migration time. Yolk sphere to perviteline space ratio in hydrated eggs and in wild common carp broodstock was calculated 1.64 which definitely yolk sphere was larger than pervitelin space. The difference between Effect of broodstock migration time on yolk sphere to perviteline space was significant (P<0.05) and was larger in initial cycle. Becase, the larger eggs in initial migration time, have longer metabolic rate.