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  • 1
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    Comparing some biological characteristics of two sturgeons species, Persian sturgeon (Acipenser persicus Borodin, 1897) and Russian sturgeon (A. gueldenstaedtii Brandt & Ratzeburg, 1833) in the Caspian Sea (2018)
    Details
    Publication Date: 2021-05-19
    Description: The objective of this study was to compare the biological parameters such as length, weight, age, caviar production indices, caviar/weight, condition factor and sex ratio of Persian sturgeon (Acipenser persicus Borodin, 1897) and Russian sturgeon (A. gueldenstaedtii Brandt & Ratzeburg, 1833) in the Caspian Sea during 1990-2014. All these characteristics (except condition factor) of Persian sturgeon were greater than the Russian sturgeon. In the long period, annually average (±SD) fork length ranged from 129.3 (±11.87) to 140.9 (±15.99) cm for Russian sturgeon and 145.7 (±17.61) to 157.4 (±19.31) cm for the Persian sturgeon. The annually caviar harvest for the Russian sturgeon ranged from 3.86 (±1.05) to 5.02 (±1.82) kg with a caviar/weight ratio were ranged from 16.9 (±4.12) to 20.1% (±5.12), while comparatively for the Persian sturgeon was greater and ranged from 4.84 (±1.62) and 7.04 (±2.58) kg with a caviar/weight ratio of 16.2 (±3.99) to 21.1% (±5.20). The age of both species ranged between 6 to 40 years but the modal age of Russian sturgeon was less than Persian sturgeon. The male:female sex ratio of Russian and Persian sturgeons were 0.23:1 and 0.57:1, respectively. The sex ratio of Russian sturgeon was significantly different from sex ratio of Persian sturgeon (p〈0.001). The condition factor of Russian and Persian sturgeons were 0.92 (±0.16) and 0.74 (±0.13), respectively. Moreover, results of the MANOVA revealed significant differences in population structure of two species (p〈0.001). Therefore, different conservation and management activities need for these two valuable sturgeons in the Caspian Sea.
    Description: Published
    Keywords: Acipenser persicus ; Acipenser gueldenstaedtii ; Age ; Length ; Weight ; Sex
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: pp.552-563
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  • 2
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    Determination of appropriate time for sturgeon catch (2018)
    Iranian Fisheries Science Research Institute | Tehran, Iran
    Details
    Publication Date: 2021-05-19
    Description: Practical phase of the project aimed at studying and determination of the most appropriate time for sturgeon catch was conducted at 10 catch stations (2 in each region) in Guilan, Mazandaran and Golestan provinces in 2002 and 2003. Number of catch stations was 4 in Guilan and Mazandaran provinces each and 2 in Golestan province. The project was carried out following the ratifications of the high committee for sustainable utilization of sturgeons which passed through in 2001. Considering the results on factors like average caviar yield, quantity and quality of produced caviar, sex composition of caught spawners and catch per unit effort we found that the average caviar yield of Persian sturgeon in all three Guilan, Mazandaran and Golestan provinces was higher in spring catch than autumn and winter and in winter catch was higher than autumn while the amount of caviar obtained was higher in autumn. Considering sex composition percentage of mature female caught was higher in spring than other seasons. Catch stations located in Guilan and western and central Mazandaran showed almost similar condition. Spring catch from late march (last 10 days) up to the 10th of May, autumn catch from late September and early October (23 September- 2 October) to the 1 st December, and winter catch from 1 st to 21st march are suitable period for catch. At the Khazarabad catch station the suitable time of catch differs from other stations therefore the proper time for catch appears to be 10- 20 may in spring and 21- 30 January in winter catch seasons. The quality and quantity of catch is suitable in spring from 21- 31 march to 21- 31 may, in autumn catch from 12- 22 October to 11- 21 December and in winter catch from 9- 19 February to 11- 20 march at catch stations located in Golestan province. As for stellate sturgeon at catch stations of Guilan and Mazandaran provinces the spring catch from 21 march specially from 21 April to 20 June was suitable and all other quantitative and qualitative factors confirmed better quality and quantity of catch in this period (21 April- 20 June) in comparison to other seasons. Gill nets (lower in number as compared to other sturgeons) could be set up beginning from 20 February to 20 March in winter catch. Our study showed quantitative and qualitative increase in catch from 9- 19 April to the end of decade from 22-31 May suggesting a suitable time of catch for stellate sturgeon in Golestan province. Based on our quantitative and qualitative results the summer catch is not suitable for Persian sturgeon and stellate sturgeon and winter catch for stellate sturgeon.
    Description: Iranian Fisheries Science Research Institute
    Description: Published
    Keywords: Sturgeon fishes ; Persian sturgeon ; Stellate sturgeon ; Time of catch ; Sex composition ; Determination
    Repository Name: AquaDocs
    Type: Report , Refereed
    Format: 112pp.
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  • 3
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    Stock assessment of juvenile sturgeons in the Iranian water of the Caspian Sea by bottom trawl survey (2021)
    In:  http://aquaticcommons.org/id/eprint/21785 | 18721 | 2017-12-03 15:07:40 | 21785 | University of Guilan, Faculty of Natural Resources, Iran
    Details
    Publication Date: 2021-07-01
    Description: The sturgeon stock assessment was performed to aim at estimation of absolute and relative abundance and determination of species composition at lower 10 m depths using the Si-Sara2 RV vessel in the Iranian coasts of the Caspian Sea in Guilan, Mazandaran and Golestan provinces during 6-30 September 2011-2012. In this study, 40 stations were selected on the basis of stratified random sampling design and then the stock estimation was performed using the swept area method. The study was carried out using bottom trawling with 9 m head rope. The time and speed of trawling in each station were 30 minutes and 2.5 knots respectively. The Catch per Unit of Effort (CPUE) in 2011–2012 were 7.03 and 6.96 individuals per trawling, respectively. The catch per unit of area in these years were found to be 1662 and 1644 fish in nm2, respectively.Total abundance of sturgeon juveniles was 13,327,164 individuals in 2011. So, the species composition included A. persicus (87.8%) and A. stellatus (12.2%). Total abundance of sturgeon juveniles was found to be 14,364,882 individuals in 2012 and the species composition comprised A. persicus (61.4%) and A. stellatus (38.6%). In 2011 the biomass of sturgeons in Iranian coastal water of the Caspian Sea was 295 tons and the composition of biomass included A. persicus (81.5%) and A. stellatus (18.5%), respectively. In the cruises conducted in 2011, this amount was estimated to be 217 tons comprising A. persicus (54.2%) and A. stellatus (45.8%), respectively. The results of this study in 2011–2012 showed remarkable abundance of juvenile sturgeons in Iranian coastal waters of the Caspian Sea in late summer and early autumn. So, by conserving these valuable stocks, the number of spawners will be increased in the future.
    Keywords: Biology ; Fisheries ; Caspian Sea ; Sturgeon ; Stock assessment ; Bottom trawling ; CPUE ; juvenile ; water ; Iranian water ; Iran ; survey ; A. persicus ; A. stellatus ; Huso huso ; spawning
    Repository Name: AquaDocs
    Type: article , TRUE
    Format: application/pdf
    Format: application/pdf
    Format: 147-156
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  • 4
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    Stock assessment of juvenile sturgeons in the Iranian water of the Caspian Sea by bottom trawl survey (2017)
    Details
    Publication Date: 2021-05-19
    Description: The sturgeon stock assessment was performed to aim at estimation of absolute and relative abundance and determination of species composition at lower 10 m depths using the Si-Sara2 RV vessel in the Iranian coasts of the Caspian Sea in Guilan, Mazandaran and Golestan provinces during 6-30 September 2011-2012. In this study, 40 stations were selected on the basis of stratified random sampling design and then the stock estimation was performed using the swept area method. The study was carried out using bottom trawling with 9 m head rope. The time and speed of trawling in each station were 30 minutes and 2.5 knots respectively. The Catch per Unit of Effort (CPUE) in 2011–2012 were 7.03 and 6.96 individuals per trawling, respectively. The catch per unit of area in these years were found to be 1662 and 1644 fish in nm2, respectively. Total abundance of sturgeon juveniles was 13,327,164 individuals in 2011. So, the species composition included A. persicus (87.8%) and A. stellatus (12.2%). Total abundance of sturgeon juveniles was found to be 14,364,882 individuals in 2012 and the species composition comprised A. persicus (61.4%) and A. stellatus (38.6%). In 2011 the biomass of sturgeons in Iranian coastal water of the Caspian Sea was 295 tons and the composition of biomass included A. persicus (81.5%) and A. stellatus (18.5%), respectively. In the cruises conducted in 2011, this amount was estimated to be 217 tons comprising A. persicus (54.2%) and A. stellatus (45.8%), respectively. The results of this study in 2011–2012 showed remarkable abundance of juvenile sturgeons in Iranian coastal waters of the Caspian Sea in late summer and early autumn. So, by conserving these valuable stocks, the number of spawners will be increased in the future.
    Description: Published
    Keywords: Survey ; Stock assessment ; Bottom trawling ; CPUE ; Juvenile ; Sturgeons ; Water
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: pp.147-156
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