اثرات پرورش ماهي كپورمعمولي در قفس بر ساختار جمعيت زئوپلانكتوني سد گلستان، استان گلستان

Impact of Common Carp cage culture on the community structure of zooplanktons in the Golestan reservoir

پرورش ماهي درقفس ازسيستم‌هاي جديدپرورش آبزيان درمحيط محصوراست، هرچند ممكن است به ­واسطه پسماند غذاي خورده نشده و مدفوع ماهيان، با ايجاد تغييرات فيزيكوشيميايي در ستون آب جمعيت زئوپلانكتوني دستخوش تغيير گردد. بدين ­منظور، اين مطالعه به پايش اثرات فعاليت پرورش ماهي كپورمعمولي در قفس بر ساختار جمعيت زئوپلانكتوني سد گلستان پرداخت. نمونه برداري در دو فصل بهار و تابستان در فواصل 5، 100، 200، 400، 1000 و 2000 متري از قفس صورت پذيرفت. نتايج نشان داد كه پرورش ماهي كپور در قفس روي خصوصيات فيزيكوشيميايي و نيز فراواني زئوپلانكتون­ ها اثر معني ­دار نداشت (0/05

Fish cage culture is a new surrounding aquaculture system. However, waste and different pollutions may alter the community structure of zooplankton in water column by physicochemical exchanges. This study was designed to monitor the impact of Common Carp cage culture on the zooplankton community structure in Golestan reservoir. In order to study the physicochemical factors of water and zooplankton population, sampling was done in two seasons of spring and summer at six stations; 5 m, 100 m, 200 m, 400 m, 1000 m and 2000m from cage. The results showed that the Common Carp cage culture did not have a significant difference on the physicochemical parameters and zooplankton abundance between seasons and stations. The most of the factors are affected by the season. In this study 10 genus of zooplankton were observed. One species from Cyrtophoridae, 2 species from Hymenostomatida, one species from Oligotrichida, 2 species from Diplostraca were identified. The other orders including Cyclopoida، Calanoida، Arcellinida and Ploima had one species each one. Cyclops has the highest abundance in spring (64%) and summer (21%) seasons. The biodiversity indices of zooplankton were lower in spring than summer. The CCA tests showed that the DO factor in the spring and NH3 in summer had a negative relationship to abundance of zooplankton. It seems the Common Carp cage culture in Golestan reservoir has no significant effect on the water quality and Structure of zooplankton population as well as the changes observed in the zooplankton structure was related to seasonal variations.