Survey on fresh water Gammarus (Gammarus fasciatus) population and its relationship with non-biotic factor in Lakanshahr stream (Rasht, Iran)

The Gammarus has been widely distributed in different part of Iran and being as a source of food for aquatic animals. There are reports regarding to ecological factors about fresh-water Gammarus in Iran. But there is very limited reports about fresh-water Gammarus in Lakanshahr altitudes. Hence, the aim of this survey was to find out the effect of abiotic factors on Gammarus population in Lakanshahr height during spring season.  

The samples were collected by means of Quadrat instrument from 10 station and measured for concentration of Gammarus. The abiotic parameters were; temperature, PH, Do2, Turbitidy and TDS.

With increasing temperature and decreasing turbidity in the month of June, the Gammarus population has been increased significantly (p˂0.05). The water parameters such as Do2 and PH has not shown significant differences in the months of spring (p<0.05); however, TDS has been decreased in the month of May and June. There is a significant correlation between temperature and Gammarus population (R2=0.948); but there is least correlation between Do2 and PH with Gammarus population (R2= 0.686) during months of spring. In addition to the nutrients of the decomposing leaf in the stream of lakanshahr in month of May and June has been increased the Gammarus population.

The result of this survey indicated that the most effective water parameters in Gammarus population are temperature and turbidity.