Considering the high value of sturgeons throughout the world, particularly Iran, the toxic effect of the insecticide 60% diazinon emulsion (2-3 L hac-1) was studied in relation to Persian sturgeon 'and Stellate sturgeon fingerlings weighing 1-3g. The acute toxicity of diazinon emulsion (60%) on the mortality of A. persicus and A. stellatus fingerlings was studied in order to determine the LC50 within 96h. The experiments were conducted in static state on the basis of TRC. The pH and total hardness of the water medium were determined during the experiment. The water temperature was 20±1oc and dissolved oxygen values were higher than 5mg L-1. The results of the studies show that the LC5096h of 60% diazinone emulsion on Persian sturgeon and Stellate sturgeon fingerlings were 4.34 mg L-1 and 2.54 mg L-1 respectively. The maximum allowabl concentration value of diazinone in Persian sturgeon and Stellate sturgeon fingerlings were 0.438 and 0.254 mg L-1 respectively. Therefore, on the basis of standards, diazinon is considered toxic for the fingerlings under study.

Motility of spermatozoa was studied on 12 and 7 specimens of Acipenser persicus and A. stellatus, respectively. The density measured to be 2.22±0.65x109ml-1 in A. persicus and 2.21±0.55x109ml-1 in A. stellatus. Semen samples were diluted with two extenders containing tris 118mM, sucrose 23.4mM, pH=8, egg yolk (20%), dimethyl sulfoxide (15%) and penicillin potassium (500IU/ml) and biociphus extender containing glycerol as a cryoprotectant at a ratio of 1:1 and then transferred to 0.5ml straws and frozen in a computer controlled low temperature apparatus and stored in liquid nitrogen for one week. To study fertilizing ability, the spermatozoa were then used to inseminate eggs after thawing. Mean sperm motility in fresh spermatozoa was 86.6% in A. persicus and 73.75% in A. stellatus which decreased to 32.2% (P<0.001) and 37.5% (P<0.001) in frozen spermatozoa, respectively. Also mean fertilization rate decreased from 90.4% to 30.7% in A. persicus and from 72% to 36.8% in A. stellatus.

Organochlorine pesticides are very important, due to their carcinogenic and delayed toxic function and their effect on nervous system of fish and human. In this study concentration of organochlorine pesticides including Lindane, Heptachlor, Dieldrin, Aldrin and DDT was measured in muscle tissues of Stellate sturgeon of southern coasts of the Caspian Sea from Astara, Hashtpar, Bandare Anzali, Kiashahr, Ramsar, Chalous, Noor, Feraidoun Kenar, Khazarabade Sari and Bandare Turkman stations. In sampled Stellate sturgeon, Heptachlor with an average concentration of 3.933 mg/kg on lipid weigth basis and Aldrin with an average concentration of <0.288 mg/kg on lipid weigth basis had the highest and lowest concentrations, respectively. The order of these pesticides according to average of concentration are as follow: Heptachlor > DDT > Lindane > Dilderin > Aldrin. Comparison of measured concentrations with Maximum Residue Limit (MRL) established by FAO/WHO showed that the average concentration of Heptachlor in all sampling stations exceeded the MRL value, also concentration of DDT in samples from Chalous and Bandare Turkman exceeded the MRL value.

In this study, the effect of 17b- estradiol on haematological indices in juvenile Stellate sturgeon (Acipenserstellatus) was investigated. For this, 120 juvenile Stellate sturgeons with an average weight of 40.9±1.1 g were divided to 2 treatments (20 fish/tank). Juvenile Stellate sturgeon, Acipenserstellatus were intraperitoneally injected with estradiol-17b (E2; 0 and 5 mg/kg fish). The duration of the experiment was considered for 7 months and at the end of the experiment, 5 fish were randomly sampled for measuring haematological indices including number of red blood cells (RBC), white blood cells (WBC), hemoglobin (Hb), hematocrit (Hct), mean corpuscular haemoglobin (MCH), mean corpuscular volume (MCV) and mean corpuscular hemoglobin concentration (MCHC). Results showed that hematological features of E2-treated fish showed significant reduction in number of red blood cells, haemoglobin concentration, hematocrit value and mean corpuscular haemoglobin (P<0.05), but no significant changes were observed in number of white blood cells, mean corpuscular volume and mean corpuscular haemoglobin concentration (P>0.05). These results revealed that the injection of E2 could cause anaemia in Stellate sturgeon.

The present study was conducted on a large number of oocytes collected from 36 female Acipenser stellatus brood fish caught from fishing grounds in the Guilan province and transferred to the Shahid Behesti sturgeon Breeding Center during 1997-1998. Physiological assessments were carried out on the microscopic sections prepared from these oocytes.Under normal conditions, 9 distinguishable layers were observed in the sections prepared from A. stellatus oocytes that included the follicle, the outer most layer, followed by a jelly coat, an external zona radiata, internal zona radiata, fat layer, pigments, cytoplasm, nucleus and nucleoli. The presence of erythrocytes and micropyle canal in the oocytes indicate normal embryognesis among them.

Background: Chondroitin sulfates (CS) is an important glycosaminoglycan’ s which is found in sturgeon fishes which are present in cartilage of these fishes. This compounds, in addition to application in food and cosmetic industries, they have clinical significant in arthritis treatment and wound healing. Materials and Methods: In present study, the chondroitin sulfate extraction was performed by using pepsin and trypsin digestions with 12 and 18 h interval times followed by cationic salt, cetylprydinium chloride (CPC) treatment. MTT assay at different incubation time (24, 48 and 72 h) was used in order to study of Chondroitin sulfate effect on induction of proliferation of fibroblasts isolated from human skin. In order to determine the proper time and enzymatic digestion, after temperature treatment of samples using pepsin and trypsin enzymes, the SDS-PAGE electrophoresis was used. And the FT-IR analysis was performed to characterize the type of CS. Results: The maximum yield of enzymatic digestion was observed for trypsin digestion at 18h, according to electrophoresis patterns. the amount of CS yield was estimated at 4. 76% in this situation. FT-IR analysis revealed that, the CS belongs to the C4S type. Chondroitin sulfates extracting from cartilage showed concentration-dependent incremental impact on fibroblast cell proliferation so that the dose-response results have shown 167% proliferation at 10 μ g/ml dose of CS compared to the control in fibroblast cells. Conclusion: Extracted CS has a positive stimulatory effect on fibroblast cells proliferation in a dose dependent manner. So it can be used for wound healing and some fibroblast related diseases.

In the last three decades, several ecological factors were changed and affected the most important commercial fish stocks in the Caspian Sea. This paper aims to assess the effects of these pressures on the population structure, stock status and the vulnerability risk of stock extinction of the Stellate sturgeon (Acipenser stellatus Pallas, 1771) in the Southern Caspian Sea, in the years 1990-2011. For this period, we estimated growth parameters, the age structure of catch, sexual maturity, age at first capture, natural and fishing mortality, biomass and risk of stock extinction of Stellate sturgeon by IUCN Red List categories. Fork lengths of individuals ranged from 82 to 206 cm and ages from 4 to 29 years. The growth parameters were L∞ =215. 0 cm, K= 0. 064 year − 1, t0=− 3. 2 years. The majority of the catch (67. 4-90. 1%, averaged 80. 0%) belonged to 913 years old. The biomass had a descending trend from 4983. 5 mt in 1990-91 declined to 10. 6 mt in 2011-12. The generation length was 16 years. Stock status indicators showed that 89% of catch were mature individuals, mature and optimum fish length comprised 74% and 10% of the fish captured comprise mega-spawners. This study revealed that the stock of the Stellate sturgeon is being overfished for the whole years and critically endangered.

sturgeon species are commercially important species in finfish aquaculture industry. Till now, a small number of studies have been reported on the immune responses in sturgeon species against infectious diseases. Monoclonal and polyclonal antibodies in fish immunoglobulins (Igs) are essential to evaluate the humoral immune response. This study aimed to produce, characterize, and evaluate the polyclonal antisera against Stellate sturgeon Igs. For the production of polyclonal antibodies against fish Igs, Stellate sturgeon serum Igs was isolated using the ammonium sulfate precipitation method. The purified Igs with the Freund adjuvant was injected subcutaneously in to sheep (Ovis aries). Then, anti- Stellate sturgeon Ig antibody titer and specificity were determined using ELISA and Western blot techniques. Stellate sturgeon Ig antibodies were detected in the immunized animals and were significantly higher in the immunized group compared to the non-immunized group. The polyclonal antisera showed a high specificity to the immunoglobulin heavy )H( chain of Stellate sturgeon and moderately cross-reacted with the immunoglobulin H chain in Siberian (Acipenser baerii) and ship (A. nudiventris) sturgeons but did not show reactivity with rainbow trout (Oncorhynchus mykiss) serum Igs. It was indicated that the produced polyclonal antisera should be further investigated to be used for immune-diagnostic purposes in sturgeon species upon exposure to various infectious diseases.

The effects of stocking density of eggs and larvae were studied related to the morphological deformities appearance, percentage of survival, and growth rate, in order to achieve the most suitable stocking density for eggs and larvae in incubators and rearing tanks. The egg stocking densities were 500, 700 and 900 g per incubator for great sturgeon, 500 and 1000g per incubator for Persian sturgeon and 400 and 425g per incubator for Stellate sturgeon. Larvae were stocked at densities of 10000, 15000 and 20000 larvae per m3 for great sturgeon, 21660, 41004 and 69000 larvae per m3 for Persian sturgeon and 15770, 23250, 57660 and 62250 larvae per m3for Stellate sturgeon. The results indicate significant differences in percentage of survived in fertilized eggs (P<0.05). By transferring the larvae into the fibreglass tanks, growth and survival rate decreased, whereas mortality and incidence of deformities increased as stocking density increased particularly on the onset of exogenous feeding. In the present study totally 20 types of deformities including bent spine, hunched back, hanging or looped tail, fin deformation, stunted body length and etc. were registered. The results showed that the morphological deformities frequency in dead and live fish were higher in high stocking densities comparing to the low stocking densities.