فهرست مطالب baharak sehhatnia

Freshwater pulmonate family Lymnaeidae are well-known for their role in transmission of diginean trematodes worldwide. The study was aimed to investigate the ecology and effects of physical and chemical components of the environment on their distribution and populaion density. The lymnaeid snails were randomly collected from 16 freshwater habitats in West Azarbaijan Province and water samples were also provided from the habitats for chemical analysis. The distribution patterns of the lymnaeid snails in all the examined sites were almost identical throughout the year except in winter. The snails were mostly found in lentic waters or slow-moving streams with muddy beds. The population densities of Lymnaea auricularia, L. gedrosiana and L. stagnalis significantly differed among the investigated waters during the course of study. The concentration of nitrate had significant positive correlations with the snails’ density while there was no significant correlation between nitrite or phosphate concentration with the population density and body size. The results indicated that distribution and density of the snails were affected by season and physicochemical characteristics of environments. These results can be useful for launching the control programs against parasitic trematodes in the region.