Assessing biotic and abiotic characteristics of fisheries communities in Shadegan Wetland

Shadegan wetland is one the international wetland which is registered in UNESCO and it is located in south of Khuzestan. This wetland have three zones: freshwater zone, intertidal zone and coastal zone with saltwater. The wetland is located in warm and arid region. This study was done in freshwater zone with the aim of finding solutions for integrated management to improve water quality of this habitat by monitoring of environmental trends and assessing the present situation. This study was done from March 2010 to February 2011 in four area of Shadegan wetland. The water quality index results showed that all stations of Shadegan wetland are categorized as group three with moderate quality. Rogbe station have the highest quality and Maleh have the lowest quality. Finally we can conclude that wastewater of sugarcane plants have negative effect and Azadegan sewage have positive effect on the wetland, and Maleh inlet can have the most negative effect on water quality. The amount of dissolved oxygen, BOD5, nitrite and phosphate decreased and conductivity, salinity, TDS and nitrate increased that can be due to water scarcity and droughts in the region. 6 class and 54 genius of phytoplankton were identified. Bacillariophycae with 20 genius have (52%) and chlorophycae with 22 genius (14%) have the highest frequency percentage of total frequency. The average value of chlorophyll a was 10.95 mg/m3 per year and the annual average primary production was 2.68 g/c/m2 in a day which Rogbe and Maleh had the highest and lowest value respectively and eutrophication floating plankton were in high mesotrophic. 18 epipleon and 27 epiphyton genius of benthic algae were identified which Bacillariophycae and cyanophycae were dominant. Chlorophyll a was the most common pigment and The wetland diversity index indicated semi polluted situation and eutrophication statues was high mesotrophic to eutrophic and based on Palmer index, the wetland had no severe organic pollution. Brachionus spp from zooplankton rotifer increased in summer due to high tolerance of salinity. Wetland zooplankton index indicates low quality of wetland situation. In substrate with vegetation, 15 groups of macrofauna of benthos were identified and Chironomidae had the highest frequency. In sedimentary substrate, 7 groups of macrobenthos were observed which in comparison to 1995 they severely decreased. These changes can be due to drought, sewage entrance, habitat degradation and ecosystem disturbances. Satellite studies of the Shadegan wetland show that 69,945 hectares are suitable for aquatic life.

Iranian Fisheries Science Research Institute

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