Relationship between biological characteristics of eggs and female brood stocks of Persian sturgeon Acipenser persicus: a comparison with other fish species.

We have determined a number of biological characteristics of the Persian sturgeon egg (including diameter, surface-to-volume ratio, yolk sphere and perivitelline space) and of female brood stocks (including age, length, weight, condition and absolute fecundity) in 420 specimens of the migratory population of Acipenser persicus in Gorgan bay of Iran from 2001 to 2004. In the hydrated egg, the average egg diameter, yolk diameter, surface-to-volume ratio and yolk sphere-to-perivitelline space ratio values were: 3.64 +/- 0.17 mm, 3.26 +/- 0.25 mm, 1.65 +/- 0.08 and 0.75 +/- 0.01, respectively. In this chondrostean species, the egg surface and volume were found to increase with increasing egg diameter, but the egg surface-to-volume ratio decreased. In Persian sturgeon, the surface-to-volume ratio and yolk sphere-to-perivitelline space ratio is very high; therefore, the metabolic rate is low and female spawning occurs in low-temperature waters. The statistical Pearson correlation between egg diameter relative to a number of brood stock characteristics, including fork length (r = 0.059), weight (r = 0.140), age (r = 0.081) and absolute fecundity (r = 0.095), were not significantly different (P > 0.05). An extensive comparison of these results with data published on other fish species is presented and discussed.