Distribution and abundance of order Ephemeroptera in Shafaroud River- Guilan Province

Distribution and abundance of order Ephemeroptera, an important insect order in running waters was examined in Shafaroud River (a river entering the Caspian Sea). For this purpose following preliminary visit to the river some 6 sampling stations were selected from upstream to the estuary of the river. Monthly sampling was carried out from July 2013 to June 2014. A Surber sampler with mesh size of 500µ and area of 0.16 m2 were used for sampling. The collected samples were isolated from debris and sediments, immediately preserved in 4% formalin solution and transferred to the laborator for identification and enumeration. Some physical such as (air and temperature )and chemical parameters of the water such as dissolved oxygen(DO), and physicochemical parameters of the water were including electron conductivity (EC)Acidity( pH) and salinity, were measured simultaneously with benthos sampling at all sampling sites. In total 8100 specimens belonging to 5 families and 9 genera of Ephemeroptera were collected and identified out of which Heptagenidae and Baetidae were the dominant families and Baetis and Rhithrogena dominant genera respectively. In most seasons Significant statistical difference were observed between upstream and downstream sampling stations (p ≤ 0.05).