تغييرات فصلي جمعيت كرم پرتار، (Nereidae) و Nereis diversicolor در اعماق مختلف ساحل بند رگز (خليج گرگان)

Population dynamics and annual biomass of the Nereis diversicolor, (Nereidae) in the Gorgan Bay (Bandargaz coast) - Southeast Caspian Sea

Population dynamics and annual biomass of the Nereis diversicolor in 1, 2 and 3 meter depths of the Gorgan Bay (Bandargaz coast) was studied in the years 2004-2005. Results revealed the highest density and biomass were in 3 meter depth in Spring and Winter and in 2 meter depth in other seasons (p<0.05). The highest and lowest average density and biomass of this worm were observed in 3 and 1 meter depths, respectively (845.37±664.06 and 658.23±622.61 ind/m2, and 2571.29±2828.56 and 2065.50±2500.26 mg/m2). significant seasonal differences in the population of this worm were observed (p<0.05), so that the highest density and biomass in all depths were encountered in Spring and the lowest density and biomass in all depths Were observed in Winter. Result of this research showed that biomass and density of this worm have increased by on comparison with the previous studies.