اﻟﮕﻮي ﺗﺨﻢ رﯾﺰي ﻣﺎﻫﯽ ﻫﻮورﻣﺴﻘﻄﯽ (Katsuwonus pelamis ) در درﯾﺎي ﻋﻤﺎن

Spawning pattern of skipjack tuna (Katsuwonus pelamis) in Oman Sea

ﺟﻤﻊ آوري اﻃﻼﻋﺎت زﯾﺴﺖ ﺳﻨﺠﯽ ﺑﻪ ﻣﻨﻈﻮر ﺑﺮر ﺳﯽ اﻟﮕﻮي ﺗﺨﻢ رﯾﺰي ﻫﻮورﻣ ﺴﻘﻄﯽ ﺻﯿﺪ ﺷﺪه ﺗﻮ ﺳﻂ ﺗﻮرﻫﺎي ﮔﻮ ﺷﮕﯿﺮ دردرﯾﺎي ﻋﻤﺎن ﺳﻮاﺣﻞ ﺳﯿﺴﺘﺎن و ﺑﻠﻮﭼﺴﺘﺎن در ﺳﺎل 1386ﺻﻮرت ﭘﺬﯾﺮﻓﺖ. اﻃﻼﻋﺎت درﺻﺪ ﻓﺮاواﻧﯽ ﻣﺮاﺣﻞ ﻣﺨﺘﻠﻒ ﺟﻨﺴﯽ ﯾﺸﺮﻓﺘﻪ و ﺷﺎﺧﺺ ﮔﻨﺎدي ﻧ ﺸﺎن داد ﮐﻪ ﯾﮏ دوره ﺗﺨﻤﺮﯾﺰي ﻃﻮﻻﻧﯽ از آﺑﺎن ﺗﺎ اردﯾﺒﻬ ﺸﺖ ﻫﻤﺮاه ﺑﺎ اوج آن درﻓﺮوردﯾﻦ-اردﯾﺒﻬ ﺸﺖ ﺑﺮاي ﺑﺮاي ﻫﻮورﻣﺴــﻘﻄﯽ در در ﯾﺎي ﻋﻤﺎن دﯾﺪه ﺷــﺪه اﺳــﺖ. ﻣﯿﺎﻧﮕﯿﻦ ﻃﻮل ﺑﻠﻮغ ﺟﻨﺴــﯽ( 50Lm) ﺑﺮاي ﻫﻮور ﻣﺴــﻘﻄﯽ ﺑﻪ ﺗﺮﺗﯿﺐ 62/4 ﺳﺎﻧﺘﯿﻤﺘﺮ ﻃﻮل ﭼﻨﮕﺎﻟﯽ ﺑﺪﺳﺖ آﻣﺪ، ﮐﻪ ﺑﺮ اﺳﺎس ﻣﻘﺎﯾﺴﻪ آن ﺑﺎ ﻓﺮاواﻧﯽ ﻃﻮﻟﯽ ﺑﯿﺶ از 70 درﺻﺪ ﻣﺎﻫﯿﺎن ﺻﯿﺪ ﺷﺪه ﻧﺎﺑﺎﻟﻎ ﻣﯽ ﺑﺎﺷﻨﺪ. ﺑﺮرﺳﯽ ﻧﺴﺒﺖ ﺟﻨﺴﯽ ﺑﻪ ﺗﻔﮑﯿﮏ ﻃﻮل ارﺟﻌﯿﺖ ﺟﻨﺲ ﻧﺮ را در ﻃﻮل ﺑﺰرﮔﺘﺮ ﻧﺸﺎن داد. راﺑﻄﻪ وزن ﺑﻪ ﺗﻔﮑﯿﮏ ﺟﻨﺲ ﻧﺮ و ﻣﺎده ﻧﺸﺎن داد ﮐﻪ در ﻃﻮل ﻫﺎي ﺑﺰرﮔﺘﺮ از61 ﺳﺎﻧﺘﯽ ﻣﺘﺮ ﻣﺎﻫﯿﺎن ﻧﺮ از وزن ﺑﯿ ﺸﺘﺮي ﻧﺴﺒﺖ ﺑﻪ ﻣﺎﻫﯿﺎن ﻣﺎده ﺑﺮ ﺧﻮردار ﻣﯽ ﺑﺎ ﺷﻨﺪ. ﺑﻪ ﻣﻨﻈﻮر ﻣﺪﯾﺮﯾﺖ ذﺧﺎﺋﺮ ﻣﺎﻫﯽ ﻫﻮور ﻣﺴﻘﻄﯽ و ﺻﯿﺪ ﺑﯿﺸﺘﺮ ﻣﺎﻫﯿﺎن ﺑﺎﻟﻎ آن دردرﯾﺎي ﻋﻤﺎن ، ﻧﯿﺎز اﺳﺖ ﺗﺎ ﭼﺸﻤﻪ ﺗﻮرﻫﺎي ﮔﻮﺷﮕﯿﺮ ﺑﻬﯿﻨﻪ ﮔﺮدﻧﺪ.

In order to determine the spawning pattern, collecting the biometric parameters for skipjack tuna wad made from artisanal gillnet fisheries during the years 2007 in Oman Sea along Sistan and Balouchestan coastal waters. The frequency of maturity stages and GSI values obtained from the species showed a long spawning period from November to May, peaking in April-May. LM50% was obtained as 62.4 for skipjack tunas, and more than 70 percent of the species was immature when compared with the length frequency of the catches. Sex ratio by size group showed a predominance of males with larger fish. Analysis of stomach contents showed a significant proportion for the species. Length-weight relationship by sex showed that in length larger than 61 cm the male accounted for the larger weight. In order to manage the skipjack resources with aiming at mature fish, it needs to use optimize the mesh sizes of gillnets.