پارامترهاي رشد و مرگ‌ومير چغوك نقره‌اي معمولي (Gerres oyena, Forsskål, 1775) در ذخيره‌گاه زيست‌كره حرا

Growth parameters and mortality rates of Gerres oyena, Forsskål, 1775 (Common silver-biddy) form Hara Biospher Reserve, Iran

ﭘﺎراﻣﺘﺮﻫﺎي ﺟﻤﻌﯿﺘﯽ ﭼﻐﻮك ﻧﻘﺮهاي ﻣﻌﻤﻮﻟﯽ )G. oyena( در ذﺧﯿﺮهﮔﺎه زﯾﺴﺖﮐﺮه ﺣﺮا در اﺳﺘﺎن ﻫﺮﻣﺰﮔﺎن از ﺷﻬﺮﯾﻮر 1395 ﺗﺎ ﻣﺮداد 1396 ﻣﻮرد ﻣﻄﺎﻟﻌﻪ ﻗﺮار ﮔﺮﻓﺖ. ﻧﻤﻮﻧﻪﺑﺮداري ﺑﺎ اﺳﺘﻔﺎده از روشﻫﺎي ﻣﺨﺘﻠﻒ ﺷﺎﻣﻞ ﺗﺮال ﻗﺎﯾﻘﯽ، ﻣﺸﺘﺎ، ﺧﻮرﺑﻨﺪ و ﺗﻮر ﻣﺤﺎﺻﺮهاي )ﭘﺎﮐﺸﯽ( ﺑﻪ ﺻﻮرت ﻣﺎﻫﺎﻧﻪ اﻧﺠﺎم ﺷﺪ. در ﻣﺠﻤﻮع 823 ﻋﺪد ﻣﺎﻫﯽ ﭼﻐﻮك ﻧﻘﺮهاي ﻣﻮرد زﯾﺴﺖﺳﻨﺠﯽ ﻗﺮار ﮔﺮﻓﺘﻨﺪ. ﻣﯿﺎﻧﮕﯿﻦ ﻃﻮل ﮐﻞ ﺑﺮاي ﭼﻐﻮك ﻧﻘﺮهاي 8/5±1/35 ﺳﺎﻧﺘﯽﻣﺘﺮ ﮐﻪ در داﻣﻨﻪ 3/9 ﺗﺎ 13/5 ﻗﺮار داﺷﺖ. راﺑﻄﻪ ﻃﻮل ﮐﻞ- وزن ﮐﻞ ﺑﺮاي ﭼﻐﻮك ﻧﻘﺮهاي ﻣﻌﻤﻮﻟﯽ W =0/0088L3/21 )R2=0/9389( ﺑﻪدﺳﺖ آﻣﺪ، ﮐﻪ ﺑﯿﺎﻧﮕﺮ رﺷﺪ ﻫﻤﮕﻮن اﯾﻦ آﺑﺰي اﺳﺖ. ﺑﺮاﺳﺎس ﯾﺎﻓﺘﻪﻫﺎي اﯾﻦ ﺗﺤﻘﯿﻖ ﭘﺎراﻣﺘﺮﻫﺎي رﺷﺪ ∞L وK ﺑﺮاي ﭼﻐﻮك ﻧﻘﺮهاي ﺑﻪﺗﺮﺗﯿﺐ 18 ﺳﺎﻧﺘﯽﻣﺘﺮ و 1/5 )در ﺳﺎل( ﺑﺮآورد ﺷﺪ. ﺷﺎﺧﺺ ﺿﺮﯾﺐ رﺷﺪ ﻣﻮﻧﺮو( 2/69 ﻣﺤﺎﺳﺒﻪ ﮔﺮدﯾﺪ. ﺑﯿﺸﯿﻨﻪ ﺳﻦ 2/1 ﺳﺎل و ﻣﯿﺰان ﻣﺮگ و ﻣﯿﺮ ﻃﺒﯿﻌﯽ )M( 2/68 در ﺳﺎل، ﺿﺮﯾﺐ ﻣﺮگ و ﻣﯿﺮ ﺻﯿﺎدي )Z( ﺑﻪ ﻣﯿﺰان 10/17 و ﺿﺮﯾﺐ ﺑﻬﺮهﺑﺮداري )E( ﺑﺮاي اﯾﻦ ﮔﻮﻧﻪ 0/74 ﺑﺮآورد ﺷﺪ. ﺑﺮ اﺳﺎس دادهﻫﺎي ﻓﺮاواﻧﯽ ﻃﻮﻟﯽ ﺑﻪدﺳﺖ آﻣﺪه ﻣﯽﺗﻮان ﮔﻔﺖ ﮐﻪ ﺟﻤﻌﯿﺖ ﻏﺎﻟﺐ اﯾﻦ ﮔﻮﻧﻪ در ﻣﻨﻄﻘﻪ ﺑﯿﺶﺗﺮ اﻓﺮاد ﺟﻮان ﺑﻮده ﮐﻪ ﺑﺮ ﻧﻘﺶ ﺣﻤﺎﯾﺘﯽ ﻣﻨﺎﻃﻖ ﭘﻮﺷﯿﺪه از ﻣﺎﻧﮕﺮو ﺑﻪﻋﻨﻮان ﻧﻮزادﮔﺎه اﯾﻦ ﻣﺎﻫﯿﺎن ﺗﺄﮐﯿﺪ ﻣﯽﻧﻤﺎﯾﺪ.

Population parameters of Common silver-biddy (Gerres oyena) were studied in Hara Biospher Reserve from September 2016 to August 2017. All fishes were sampled by boat trawl, beach seine and trapping barriers. Growth parameters were determined using the monthly length–frequency data. The Mean total length was calculated 8.5±1/35 cm for Common silver-biddy. The value of L∞ and K were calculated 18 cm and 1.5 yr-1 respectively. The rate of natural mortality (M) were estimated 2.68 yr-1. The length-weight relationship were determined as W= 0.0088 L 3.21 and W= 0.00887L 3.21 for Common silver-biddy. Results showed these fishes were juvenile and emphasized on supporting roles of creeks for Gerridae as nursery ground.