Distribution, diversity and abundance of fish species in the Madarsoo River, Golestan National Park, Iran

Abstract

To assess the effects of two flooding events occurred in the years 2001 and 2002, fish distribution, diversity and abundance in Madarsoo River of the Golestan National Park were studied and compared to that of the years before the events. A total of five fish species from four sites were collected. Assemblage of fish population showed changes in their overall relative abundance and distribution across sampling sites and times. We estimated the abundance of Capoeta capoeta gracilis at 2.331:2.6, Alburnoides bipunctatus at 0.17±0.15, Paracobitis malapterura at 0.0474±0.031 and Leuciscus cephalus at 0.005±0.01 fish per square meter of the stream. The abundance of Cc.gracilis showed significant increase while that of the A. bipunctatus did not undergo such significant change in comparison with the data from the years before flooding events (P<0.01). The Shannon diversity index was significantly different between sites and with the increase in the number of riffles and pools in the river, the index and population size of the fish species showed an upward trend. Three fish species Oncorhynchus mykiss, Neogobius melanostomus affinis and Neogobius fluviafilis which were abundant before the floods did not show up in the samples at all. Also, of the Barbus mursa, only one specimen was caught. Canonical correspondence analysis (CCA) results suggest that two species C. c. gracilis and P. malapterura are more resistant against changes in environmental conditions.