تعیین منا سب ترین سن و وزن بچه ماهی ازون برون (acipenser stellatus) برای رهاسازی به دریای خزر

اﻣﺮوزه ﺗﮑﺜﯿﺮ ﻣﺼﻨﻮﻋﯽ ﻣﺎﻫﯿﺎن ﺧﺎوﯾﺎری، ﺗﻨﻬﺎ روش ﺟﻬﺖ ﺑﺎزﺳﺎزی ذﺧﺎﯾﺮ، اﯾﻦ ﮔﻮﻧﻪﻫﺎی ﺑﺎ ارزش ﻣﯽﺑﺎﺷﺪ. در اﯾﻦ ﭘﮋوﻫﺶ، 1200 ﺑﭽﻪ ﻣﺎﻫﯽ ازونﺑﺮون در ﭼﻬﺎر ﺗﯿﻤﺎر ﺳﻨﯽ و وزﻧﯽ ﻣﺨﺘﻠﻒ ﺷﺎﻣﻞ ﺗﯿﻤﺎر a 55 روزه 0/5-1 ﮔﺮم ، ﺗﯿﻤﺎر b 69 روزه 1-3 ﮔﺮم ، ﺗﯿﻤﺎر c 77 روزه 3-5 ﮔﺮم ، و ﺗﯿﻤﺎر d 85 روزه 5-10 ﮔﺮم در 12 ﻣﺨﺰن 2 ﺗﻨﯽ ﺑﺎ آب درﯾﺎ، ﭼﺎه و ﻣﺨﻠﻮط آن ﻫﺎ ﺑﻪ ﻫﻤﺮاه ﻫﻮاده ﺑﺎ ﺗﺮاﮐﻢ 100 ﻋﺪد در ﻫﺮ ﻣﺘﺮﻣﺮﺑﻊ ذﺧﯿﺮهﺳﺎزی ﺷﺪﻧﺪ. 4 آزﻣﺎﯾﺶ در ﺷﻮریﻫﺎی ﻣﺨﺘﻠﻒ 4-9 ،0/5-4 ،0-0/5 و 9-13 ﮔﺮم در ﻫﺰار و ﻫﺮآزﻣﺎﯾﺶ در 4 ﺗﯿﻤﺎر و ﻫﺮ ﺗﯿﻤﺎر ﺑﺎ 3 ﺗﮑﺮار ﻃﺮاﺣﯽ و در ﻣﺪت زﻣﺎﻧﯽ ﺗﻘﺮﯾﺒﺎً ﯾﮏ ﻣﺎه ﺑﻪ ﻫﻤﺮاه ﻏﺬادﻫﯽ ﺑﺎ ﻏﺬای زﻧﺪه ﺗﺮﺟﯿﺤﺎً ﮔﺎﻣﺎروس، ﮐﺮم ﻧﺮﺋﯿﺲ، ﺷﯿﺮوﻧﻮﻣﯿﺪه در ﺣﺪ اﺷﺒﺎع 6 وﻋﺪه در روز و ﺳﯿﻔﻮن و ﺗﻌﻮﯾﺾ آب ﻣﺪاوم و ﺟﺎری ﻧﯿﺰ اﻧﺠﺎم ﭘﺬﯾﺮﻓﺖ. زﯾﺴﺖﺳﻨﺠﯽ ﻫﺮ 10 روز ﯾﮑﺒﺎر اﻧﺠﺎم ﺷﺪ. ﺑﺮ اﺳﺎس ﻧﺘﺎﯾﺞ، ﺑﭽﻪ ﻣﺎﻫﯽ ازون ﺑﺮون در دوره ﭘﺮورﺷﯽ 55 روزه 0/5-1 ﮔﺮم ﺑﻌﺪ از 15 روز ﭘﺮورش ﺑﻪ رﺷﺪی در ﺣﺪود 1 ﮔﺮم رﺳﯿﺪ. در دوره ﭘﺮورش 69 روزه 1-3 ﮔﺮم ﺑﭽﻪ ﻣﺎﻫﯿﺎن ﺑﻪ ﻣﯿﺎﻧﮕﯿﻦ وزﻧﯽ 5 ﮔﺮم ﺑﻌﺪ از 24 روز ﭘﺮورش رﺳﯿﺪﻧﺪ. در دوره ﭘﺮورش 77 روزه 3-5 ﮔﺮم ، ﺑﻌﺪ از 24 روز ﭘﺮورش ﺑﭽﻪ ﻣﺎﻫﯿﺎن ﺑﻪ ﻣﯿﺎﻧﮕﯿﻦ وزﻧﯽ 7 ﮔﺮم رﺳﯿﺪﻧﺪ. در دوره ﭘﺮورش 85 روزه 5-10 ﮔﺮم ، ﺑﭽﻪ ﻣﺎﻫﯿﺎن ﺑﻪ ﻣﯿﺎﻧﮕﯿﻦ وزﻧﯽ 14 ﮔﺮم ﺑﻌﺪ از 26 روز ﭘﺮورش رﺳﯿﺪﻧﺪ. زﻣﺎﻧﯽ ﮐﻪ ﺑﭽﻪ ﻣﺎﻫﯿﺎن ازون ﺑﺮون در ﺷﻮریﻫﺎی ﻣﺨﺘﻠﻒ ﻗﺮار ﮔﺮﻓﺘﻨﺪ، درﺻﺪ ﺗﻠﻔﺎت ﮐﻢ ﺗﺮی را ﻧﺴﺒﺖ ﺑﻪ ﺗﯿﻤﺎرﻫﺎی دﯾﮕﺮ 65 و 70 0/5 ﺗﺎ 1 و 1 ﺗﺎ 3 ﮔﺮم ﻧﺸﺎن دادﻧﺪ. ﺑﯿﺶ ﺗﺮﯾﻦ درﺻﺪ ﺗﻠﻔﺎت ﻣﺮﺑﻮط ﺑﻪ دورهﻫﺎی ﭘﺮورش 55 و 69 روز ﺑﺎ ﻣﯿﺎﻧﮕﯿﻦ وزﻧﯽ 0/5 ﺗﺎ 1 و 1 ﺗﺎ 3 ﮔﺮم در ﺗﯿﻤﺎرﻫﺎی a و b ﺑﻮد. ﺑﯿﺶ ﺗﺮﯾﻦ درﺻﺪ ﺗﻠﻔﺎت در ﺷﻮری ﻫﺎی ﺑﺎﻻ 9-4 و 9-13 ﮔﺮم در ﻫﺰار ﻣﺮﺑﻮط ﺑﻪ ﮔﺮوه ﺳﻨﯽ 0/5 ﺗﺎ 3 ﮔﺮم ﺑﻮد. ﻧﺘﺎﯾﺞ ﭘﮋوﻫﺶ ﺣﺎﺿﺮ ﻧﺸﺎن داد ﺑﻬﺘﺮﯾﻦ دوره ﭘﺮورش ﺟﻬﺖ رﻫﺎﺳﺎزی ﺑﭽﻪ ﻣﺎﻫﯽ ازونﺑﺮون ﺑﻪ درﯾﺎ ﺷﻮری 9-13 ﮔﺮم در ﻫﺰار در ﻣﺪت زﻣﺎنﻫﺎی 77 و 85 روز 3 ﺗﺎ 5 و 5 ﺗﺎ 10 ﮔﺮم ﺑﻮد ﮐﻪ ﮐﻢ ﺗﺮﯾﻦ ﻣﯿﺰان ﺗﻠﻔﺎت را داﺷﺖ.

determining the most suitable age and weight of fingerlings stellate fish (acipenser stellatus) for release into the caspian sea

nowadays, the artificial reproduction of sturgeon fish is the only method to restore the stocks of these valuable species. 1200 stellate a. stellatus fingerlings at different ages of 55, 69, 77 and 85 days – old were stored at a density of 100 per square meter in 12 tanks 2-ton with sea water, hole water and their mixture and treated in four rearing treatments including a: 55 days 0.5-1 g , b: 69 days 1-3 g , c: 77 days 3-5 g and d: 85 days 5-10 g and also 4 treatments in different salinities 0.5, 0.5-4, 4-9 and 9-13 g/thousand . each treatment was designed with 3 repetitions. each experiment was carried out in a period of approximately one month along with feeding with live food, preferably gamarus, nereis worm, shironomide at the saturation level of 6 meals a day, and siphoning and changing water continuously. biometry was done every 10 days. according to the study, a. stellatus fish fingerlings reached a growth of about 1 gram after 15 days of rearing in the 55-day rearing period 0.5-1 g . in the breeding period of 69 days 1-3 grams , after 24 days of rearing, the fingerlings reached an average weight of 5 grams. in the breeding period of 77 days 3-5 grams , after 24 days of rearing, the fingerlings reached an average weight of 7 grams. in the breeding period of 85 days 5-10 grams , after 26 days of rearing, the fingerlings reached an average weight of 14 grams. when the fingerlings of a. stellatus were placed in different salinities, they showed a lower percentage of mortality compared to other treatments, 65 and 70 0.5 to 1 and 1 to 3 grams of treatments a and b. the highest percentage of losses was related to breeding periods of 55 and 69 days with average weight 0.5 to 1 and 1 to 3 grams in treatments a and b. the highest percentage of losses in high salinities 9-4 and 9-13 g/thousand was related to the age group 0.5 to 3 g. the results of the present research showed that the best rearing period for releasing the fingerlings into the sea salinity 9-13 g/thousand was in the period of 77 and 85 days 3-5 and 5-10 g , which had the lowest mortality.