ماکروبنتوز، نهر مادرسو، فراوانی
Subject Areas : New Technologies in Aquaculture Development
S. Jorjani
1
(Faculty members Dept. of Fisheries, Islamic Azad University, Azadshahr branch)
A. Ghelichi
2
(Faculty members Dept. of Fisheries, Islamic Azad University, Azadshahr branch)
R. Akrami
3
(Faculty members Dept. of Fisheries, Islamic Azad University, Azadshahr branch)
V. Kheirabadi
4
(Faculty members Dept. of Fisheries)
Keywords: frequency, macrobenthose, Madarsu Stream,
Abstract :
This study was conducted to identification of macrobenthoses in Madarsu Stream to evaluation of quality of water. Sampling was being done from April 2006 to March 2007. Macrobenthoses samples were collected by Surber sampler (30×30cm). The collected benthoses were fixed in 4% formaldehyde solution and transferred to the laboratory. In each station while sampling, discharge and water temperature were also measured. The most frequent orders were Ephemeroptera, Trichoptera and Diptera. Among Diptera three families of Chironomidae, Simulidae and Tabanidae had been dominant with the frequency of 64, 17 and 17 percents respectively. The maximum number of Ephemeroptera and Trichoptera was seen in mid August, while in Diptera the maximum was observed in May and early February. The decrease in the number of Diptera could have been because of water high discharge during March. Considering frequency of benthic fauna in different months, Ephemeroptera was dominant. But in some station (esp. the 5th one) because of entering of Tangerah village sewage of restaurants to this part of stream Diptera was dominant. The number of Diptera (especially Diptera) had a considerable decrease during summer. It could have been because of vertical migration of this benthos from bottom to surface and feeding activity of benthos feeders in particular. Because of Madarsu bed-stream which is rubble-stony in most places, low amount of organic materials in water, there were not differences in stations. To sum it up, the water in Madarsu stream has high quality. Occurrence of seasonal floods during early August causes significant decrease in the number of macrobenthoses and diversity in the stream reduced because of occurrence of floods in the past years.
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