تعيين ﺷﺎﺧﺺ ﻣﻄﻠﻮﺑﯿﺖ زﯾﺴﺘﮕﺎه و ﻣﻬﻤﺘﺮﯾﻦ ﻋﻮاﻣﻞ اﺛﺮﮔﺬار ﺑﺮ اﻟﮕﻮي ﭘﺮاﮐﻨﺶ ﺳﯿﺎهﻣﺎﻫﯽ -Capoeta razii Jouladeh Roudbar, Eagderi, Ghanavi and Doadrio, 2017 در رودﺧﺎﻧﻪ رودﺑﺎﺑﻞ، اﺳﺘﺎن ﻣﺎزﻧﺪران

Determination of Habitat Suitability Index and the most significant factors on distribution pattern of Capoeta capoeta in Roodbabol River, Mazandaran Province.

ﺣﻀﻮر-ﻋﺪمﺣﻀﻮر و ﻓﺮاواﻧﯽ ﻫﺮ ﮔﻮﻧﻪ ﻣﺎﻫﯽ در ﯾﮏ زﯾﺴﺘﮕﺎه رودﺧﺎﻧﻪاي ﺗﺤﺖﺗﺄﺛﯿﺮ ﻋﻮاﻣﻞ ﻣﺘﻌﺪدي ﻗﺮار ﻣﯽﮔﯿﺮد و آنﻫﺎ داﻣﻨﻪﻫﺎي ﺧﺎﺻﯽ )ﻣﺤﺪود ﯾﺎ وﺳﯿﻊ( از ﺗﻐﯿﯿﺮات ﻫﺮ ﻓﺎﮐﺘﻮر زﯾﺴﺘﮕﺎﻫﯽ را ﺗﺮﺟﯿﺢ ﻣﯽدﻫﻨﺪ. ﻣﻄﺎﻟﻌﻪ ﺣﺎﺿﺮ ﺑﺎ ﻫﺪف ﺑﺮرﺳﯽ ﺷﺎﺧﺺ ﻣﻄﻠﻮﺑﯿﺖ زﯾﺴﺘﮕﺎه ﺳﯿﺎهﻣﺎﻫﯽ )C. razii( و ﺗﺄﺛﯿﺮ ﻋﻮاﻣﻞ زﯾﺴﺘﮕﺎﻫﯽ ﺑﺮ ﭘﺮاﮐﻨﺶ و ﻓﺮاواﻧﯽ آن در رودﺧﺎﻧﻪ رودﺑﺎﺑﻞ، از ﺳﺮﺷﺎﺧﻪﻫﺎي ﺑﺎﺑﻠﺮود، اﺳﺘﺎن ﻣﺎزﻧﺪران اﻧﺠﺎم ﮔﺮﻓﺖ. ﺑﺮاي اﯾﻦ ﻣﻨﻈﻮر ﻧﻤﻮﻧﻪﺑﺮداري از ﻣﺎﻫﯿﺎن در ﻃﯽ دو ﻫﻔﺘﻪ اول در دي ﻣﺎه 1396 در 20 اﯾﺴﺘﮕﺎه اﻧﺠﺎم و در ﻫﺮ اﯾﺴﺘﮕﺎه 10 ﻓﺎﮐﺘﻮر زﯾﺴﺘﮕﺎﻫﯽ اﻧﺪازهﮔﯿﺮي ﺷﺪ. در ﮐﻞ دوره، ﻧﻤﻮﻧﻪﺑﺮداري از ﻫﺮ اﯾﺴﺘﮕﺎه ﯾﮑﺒﺎر ﺻﻮرت ﮔﺮﻓﺖ. ﺳﭙﺲ ﻣﻨﺤﻨﯽﻫﺎي ﻣﻄﻠﻮﺑﯿﺖ زﯾﺴﺘﮕﺎه ﺑﺮاي ﻫﺮ ﯾﮏ از ﻣﺘﻐﯿﺮﻫﺎ و در ﻫﺮ اﯾﺴﺘﮕﺎه ﺑﺎ اﺳﺘﻔﺎده از ﻧﺮماﻓﺰار HABSEL ﺑﻪدﺳﺖ آﻣﺪ. ﻫﻤﭽﻨﯿﻦ ﺗﻌﯿﯿﻦ اﻟﮕﻮي ﭘﺮاﮐﻨﺪﮔﯽ ﺑﺎﺗﻮﺟﻪ ﺑﻪ ﻓﺮاواﻧﯽ ﺳﯿﺎهﻣﺎﻫﯽ در ﻫﺮ اﯾﺴﺘﮕﺎه و ارﺗﺒﺎط ﺑﻬﺘﺮﯾﻦ ﻣﺘﻐﯿﺮﻫﺎي زﯾﺴﺘﮕﺎﻫﯽ ﺑﺎ آن از ﻃﺮﯾﻖ آﻧﺎﻟﯿﺰ dbRDA در ﻧﺮماﻓﺰار 6-Primer+Permanova اﻧﺠﺎم ﮔﺮﻓﺖ. ﺑﺮاﺳﺎس ﻧﺘﺎﯾﺞ ﺣﺎﺻﻞ از آﻧﺎﻟﯿﺰ HABSEL ﺳﯿﺎهﻣﺎﻫﯽ در ﺳﺮﺷﺎﺧﻪ رودﺑﺎﺑﻞ، ﻣﮑﺎنﻫﺎﯾﯽ ﺑﺎ ﻋﺮض زﯾﺎد، ﺳﺮﻋﺖ ﺟﺮﯾﺎن ﮐﻢ، دﻣﺎي 14 ﺗﺎ 18 درﺟﻪ ﺳﺎﻧﺘﯽ ﮔﺮاد، ﻋﻤﻖ ﻣﺘﻮﺳﻂ )22 ﺗﺎ 30 ﺳﺎﻧﺘﯽ ﻣﺘﺮ(، ارﺗﻔﺎع ﻣﺘﻮﺳﻂ )140-180 ﻣﺘﺮ(، ﺿﺮﯾﺐ ﻫﺪاﯾﺖ اﻟﮑﺘﺮﯾﮑﯽ )260-300 ﻣﯿﮑﺮوزﯾﻤﻨﺲ ﺑﺮ ﺳﺎﻧﺘﯽﻣﺘﺮ(، ﻗﻠﻮه ﺳﻨﮓﻫﺎي رﯾﺰ )100-125 ﻣﯿﻠﯽﻣﺘﺮ(، اﮐﺴﯿﮋن ﻣﺤﻠﻮل ﺑﺎﻻ )12-13 ﻣﯿﻠﯽﮔﺮم ﺑﺮ ﻟﯿﺘﺮ(، ﭘﻮﺷﺶ ﮔﯿﺎﻫﯽ )درﺧﺘﭽﻪزار و ﺑﻮﺗﻪزار( ﺑﻪﻫﻤﺮاه ﺳﺎﯾﻪ )41 ﺗﺎ 70%( را ﺗﺮﺟﯿﺢ ﻣﯽدﻫﺪ. ﻫﻤﭽﻨﯿﻦ ﮔﺮاف dbRDA ﺑﺮاﺳﺎس ﻣﺪل DistLM ﻧﺸﺎن داد ﻣﺘﻐﯿﺮﻫﺎي ﻋﻤﻖ و ﻋﺮض رودﺧﺎﻧﻪ در درﺟﻪ اول و ﺳﺮﻋﺖ ﺟﺮﯾﺎن و ﺿﺮﯾﺐ ﻫﺪاﯾﺖ اﻟﮑﺘﺮﯾﮑﯽ در درﺟﻪ دوم در اﯾﺠﺎد اﺧﺘﻼﻓﺎت ﻓﺮاواﻧﯽ ﺳﯿﺎهﻣﺎﻫﯽ ﻣﯿﺎن اﯾﺴﺘﮕﺎهﻫﺎي ﻣﺨﺘﻠﻒ ﻧﻘﺶ داﺷﺘﻨﺪ.

Presence-absence and abundance of each fish species in a river habitat depends on several factors and they prefer a specific range of each habitat factor. The present study was carried out to investigate habitat suitability index of Capoeta capoeta and the effect of habitat factors on its distribution and abundance in Roodbabol branch of the River Babolrood (Mazandaran Province). To do, fish sampling was performed at 20 sampling stations during December 2017 and January 2018 and 11 habitat factors were measured at each sampling station. Then, habitat suitability curves for each parameter and suitability index of each station were obtained using HABSEL software. Also, determination of distribution pattern of C. capoeta and its relation with the best habitat factors were surveyed using dbRDA analysis according to its abundance at each station in Primer+Permanova (Ver. 6).Based on the HABSEL results, C. capoeta inhabiting in Roodbabol prefers wide locations with low water flow speed, temperature between 14 to 18°C, average depth (22 to 30 cm), average altitude (140-180 m), average EC (260-300 μS/cm), small grain size of substrate rocks (100-125 mm), high level of dissolved oxygen (12 to 13 mg/l), and average salinity (1.5-1.7 mg/l) which are covered by bush and shrubs and shadow level is 41-70%. Also, dbRDA graph based on DistLm model indicated that factors of depth and width in the first order and water flow with EC in the second order affected the abundances differences of C. capoeta among various stations.