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  • 1
    Publication Date: 2021-05-19
    Description: This study was carried out on 16 Sturgeon spawner(6 ship and 10 persian sturgeon) which were operated in shahid Dr. beheshti Rearing and Propagation Complex during 2001, 2002 and 2003. surgery performed on 16 spawners (6 ship sturgeon and 10 persian sturgeon). operation fulfilled in 3 ways: 1- without anesthesia 2- anesthesia by injection of Chanazin 2%(4 to 10 mg for per kilogram of fish body weight) 3- anesthesia by replacing fish in clove powder solution. In the surgery operation without anesthesia, the fish maintained by three persons and the eggs removed. In the case of applying anesthesia, 2% Chanazin, with commercial name Rompun(20 mg/ml), 4- 10 mg for per kilogram of body weight injected, but the rate of clove Powder application was 150 200 mg/l.surgery carried out by Kosarva method(making slight cut on Ventral area stitching). The cut length was 6-8 cm. The cut site stitched by Kapron unabsorbable thread and single knot with 6 to 7 mm distance.The mean weight of female spawners of ship(Acipenser nudiventris) was 35.3 ± 8.3 kg(n=6) which 3.9 ± 0.89 kg caviar, removed on average(11% of total body weight). The mean weight of female spawners in Persian sturgeon(Acipenser persicus) was 23.6 ± 3.2 kg(n=10) that the mean rate of caviar removed was 2.7 ± 0.62 kg(11.4% of total body weight). Investigation on reared spawner of ship(Acipenser nudiventris, n=16) and Persian sturgeon (Acipenser persicus,n=60) without surgical operation showed that the average body weight of spawners was 43.7 ± 8.8 kg and 28.9 ± 6.4 kg and the mean rate of caviar removal was6.4 ± 1.7 kg (15.7% of total body weight) and 4.4 ± 1.3 kg (15.4% of total body weight) respectively. During 2001, surgical operation performed on 8 spawners(5 ship and 3 persian sturgeon) which one Persian sturgeon and 2 ship after one day, one ship after 3 days and two ship after 32 days and 105 days and 2 persian sturgeon after 91 and 136 days were died. During 2002, totally five Persian sturgeon were operated which all of them died after 46,116,130,132 and 157 days. During 2003, 3 spawners(2 persian sturgeon and one ship) were operated which two Persian sturgeon died after 23 and 59 days and one ship spawnerdied after 72 days. This mortality can be due to not feeding of formulated food and even live food by the wild spawners after surgery. Also, other factors can be mentioned, such as existence of otter in the ponds with spawners are kept, breaking of swim bladder during egg sampling in catch stations & hatcheries small area for maintaining spawners after surgery and not tolerating of surgical operation by some spawners. It should be mentioned that surgery point has been fully improved in the spawners that survived more than 40 days after surgery. The results of the study indicated that removal of caviar from wild spawners is possible, but maintaining them in freshwater to remove caviar again, can be problematic. So, the surgery for caviar removal & removing of caviar for second time in following years should be carried out only on reared spawners.
    Description: Iranian Fisheries Science Research Institute
    Description: Published
    Keywords: Sturgeon fish ; Surgery ; Caviar removal ; Acipenser nudiventris ; Acipenser persicus
    Repository Name: AquaDocs
    Type: Report , Refereed
    Format: 38pp.
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  • 2
    Publication Date: 2021-05-19
    Description: The operations of this project commenced with the capture and tagging of four spawners in the spring of 2006 and 2007 in the Sepidrud River. Three male Acipenser persicus spawners and one male A. stellatus spawner were collected by beach seine (120 m long, 6 m high and mesh size of 10 and 15 cm) and waiting nets. Spawners were tagged with radio transmitters with a frequency between 150-151 MHz. These transmitters were used for the first time in Iran on fish. Signals were received using a radio receiver model WTI-1000 (Wildlife Track Inc.) with Yagi antennae and a Telex ProAir 1500 earphone. Tagged spawners were tracked from the land (along the river margin) and in water in motor boats. The aim of this study was to study the potential for migration and natural reproduction in sturgeons in the Sepidrud River. Water temperature during the study period varied between 12-26 ֯C in the first year and between 16-22 ֯C in the second year of the study. The A. stellatus spawner weighed 6 kg while the A. persicus spawners weighed between 11 to 25 kg. Sperm motility of A. stellatus spawner was 39%, sperm density was 0.42x109 ml and motility time was 15 sec., while in A. persicus spawners, sperm motility varied between 50-65%, sperm density was between 0.500x109 to 0.865x109 ml and motility time of sperms varied between 20-42 sec. Tracking tagged spawners revealed that A. stellatus spawners moved at an average speed of 1100 m h-1 (influenced by the strong currents in the river) while A. persicus spawners moved downstream at an average speed of 90 m h-1. Results of the present study indicate the presence of potential barriers such as water temperature, river water flow, physiological conditions of spawners in terms of sexual maturity, and the presence of fishers and fishing gear, for the migration of sturgeon spawners in the Sepidrud River. However the spawners were able to escape the various fishing gear set up in the Sepidrud River and return to the sea, indicating the possibility of natural reproduction in this river.
    Description: Iranian Fisheries Science Research Institute
    Description: Published
    Keywords: Physiological ; Radio transmitters ; Migration ; Sturgeons ; Spawners ; Male ; Acipenser persicus ; A. stellatus ; Temperature ; A. persicus ; Sperm ; Motility ; Sexual maturity
    Repository Name: AquaDocs
    Type: Report , Refereed
    Format: 60pp.
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  • 3
    Publication Date: 2021-05-19
    Description: The severe decrease in fish stocks particularly those of sturgeon stocks in the Caspian Sea and the increasing attention given to the rehabilitation of these stocks and so also the failure in natural breeding due to the insufficient number of broodfishes and deterioration of natural spawning grounds were some of the reasons that induced the formation of broodfish shoals under the artificial conditions available at the fish breeding and cultivation centers. The present study was conducted in three stages. I Selection of broodfishes from hatchery reared fishes: On the basis or the results obtained from the biometric measurements conducted on 663 two year old sturgeons reared in the Shahid Dr. Beheshti Center, 193 fish were selected. These fishes were grouped in three groups and marked. The first group consisted of 86 fishes with an average of 1708 5 g, LX = 13.82 cm and an average conditional factor of 0.653. 12.97 per cent of the fishes measured were placed in this group. The second group consisted of 76 fishes with an average weight of 2148.7 average LX z: 15.62 cm and an average conditional factor of 0.639. 11.46 per cent of the fishes measured were placed in this group. The third group consisted of 31 fishes with an average weight of 2216.13 g, average LX = 16.68 and an average conditional factor of 0.642. This group cotnprised 4.68 per cent of the fishes measured. 2. Formation of broodfish shoals from naturally produced broodfishes: In this stage 43 Kg eggs were harvested from 12 live female Persian sturgeon broodfishes and 16.2 Kg eggs were harvested from 3 live female ship sturgeon brood fish through incision of the abdomen. 3. Formation of broodfish shoals from larvae and fingerlings reared in vniro tanks: In this stage of the study larvae of stellate sturgeon (average weight of 0.138 g) ship sturgeon (average weight of 0.279 g) and Persian sturgeon ( average weight of 0.155 g) as well as fingerlings of great sturgeon with an average weight of 13.2 g were used. Keywords: Sturgeon, broodfish shoals.
    Description: Iranian Fisheries Science Research Institute
    Description: Published
    Keywords: Biotechnique ; Breeding ; Hatchery ; Sturgeon
    Repository Name: AquaDocs
    Type: Report , Refereed
    Format: 59pp.
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