Relationship between Biological Egg Characteristics and Female Brood Fish in Stellate Sturgeon, Acipenser stellatus Pallas, 1771 (Pisces: Acipenseridae) in the Southeast Caspian Sea, Iran
Fecundity is one of the important indicators of reproduction biology in fishes especially in rearing and restocking management of endangered species such as sturgeon. The fecundity of stellate Sturgeon (Acipenser stellatus Pallas, 1771) was studied in 50 specimens captured by gill net (mesh size= 100 mm) and seine net in different fishing areas along the southeastern part of the Caspian Sea from October 2004 through June 2005.Some biological characteristics of eggs (including diameter, surface-to-volume ratio of egg) and of fish (including age, fork length, weight, fecundity and gonadosomatic indices) were determined, and the relationship between them was defined. The results obtained showed that eggs were in stage F5 of development, and mean fork length, weight, age, fecundity and gonadosomatic indices were 125.26±8.01 (cm), 10.3±1.97 (kg), 12±1.34 (years), 170730±43211.11 and 20.88±3.19 (%), respectively. Also, the average egg diameter and surface-to-volume ratio were 2.92±1.44 (mm) and 2.06±0.12 (mm-1), respectively. Positive correlation was detected between egg diameter and surface, and volume, while negative correlation was found between egg diameter and surface-to-volume ratio. Weight, length and age have linear relationships with absolute fecundity and age was the best predicator of fecundity (r2= 0.848, F=27.962 and P value=0.003).