---

In the present study, a piece of the ovary of a 6 years old female Sterlet sturgeon (A. ruthenus), a farmed fish (729 g and 47.3 cm), was removed after anaesthetizing with clove carpel powder (0.4 g/lit). Ovarian follicles were isolated from each other and were washed using sterile phosphate-buffered saline (PBS) containing antibiotics. Follicular cells were then separated by treating oocytes with 0.25% Trypsin-EDTA in Ca2+ and Mg2+ free PBS and were cultured in medium L-15 supplemented with 20% FBS at 22°C (1.25×106cells/ml). After twelve days, when confluent monolayer cells covered the bottom surface of the flask, the cells were dislodged by Trypsin-EDTA solution (0.25%), and were then washed with PBS containing antibiotics and sub-cultured. In the experiments, ovarian follicular cell were cultured in L-15, DMEM/F12 and M199 media, 10%, 15% and 20% of FBS, and were incubated at 20°C, 22°C and 25°C. Cells in L-15 showed better growth but no cell growth observed in the other media. The cells could grow at temperature between 20°C and 22°C, and the results showed that the optimum temperature for cell growth was 22°C.  In addition, the growth rate of follicular cells increased when the FBS proportion increased from 10% to 20%, with the optimal growth at the concentrations of 20% FBS. Most proliferation of cells obtained when the L-15 medium was supplemented with 20% FBS and the incubation temperature was 22°C. The most proliferation of cells obtained in L-15 medium with 20% FBS at 22°C. 

---

The aim of this study was to record growth parameters, mortality and sex ratio of Stellate Sturgeon (Acipenser stellatus) from the south basin of the Caspian Sea. 894 specimens were caught by fixed gill net and beach seine during April 2010 to March 2014. Male to female sex ratio was obtained 1:1.05 that was not differed significantly (p>0.05). The minimum and maximum length of the fish specimens ranged from 35 cm to 170 cm (for male) and 105 cm to 214 cm (for female), respectively. Mean (±S.D) total length was calculated 129.67±15.22 cm and 148.02±12.67 cm for male and female, respectively. The maximum frequency of length was 120-130 cm and 140-150 cm for male and female, respectively. The b value of the length-weight relationship for male was 3.074 that showed isometric growth (p>0.05) and for female was 3.209 that showed positive allometric growth (p<0.05). Total mortality (Z), natural mortality (M) and fishing mortality (F) were calculated (0.535, 0.222 and 0.313 year^-1) and (0.465, 0.22 and 0.245 year^-1) for male and female, respectively. Also exploitation rates (E) were obtained 0.59 and 0.53 for male and female, respectively. Estimated Von Bertalanffy growth parameter values were (L_∞ = 187.54 cm, K = 0.15 year^-1 and t₀ = -0.32 year) and (L_∞ = 195.00 cm, K = 0.14 year^-1 and t₀ = -0.25 year) for male and female, respectively. Also infinity weights (W_∞) were estimated 21435 g and 26258 g for male and female, respectively. T_max values (maximum length) were calculated 20 years and 21.43 years for male and female, respectively. Growth performance index (ϕ) was calculated 3.72 and 3.73 for male and female, respectively. Estimated logistic growth parameter values were (β₁ (L_∞) = 188.00 cm and β₂ (growth-at-hatch) = 5 cm) and (β₁ (L_∞) = 190.00 cm and β₂ (growth-at-hatch) = 5 cm) for male and female respectively. Based on the results, Acipenser stellatus stocks have unfavorable conditions in the south basin of the Caspian Sea, and the management measures are necessary to preserve and restore the remaining stocks of this species in the ecosystem.