Identification and determination of density and biomass of polychaetes in Chalus Shore, Caspian Sea

Fluctuations of density and biomass of polychaetes in four stations at southern Caspian Sea was measured seasonally. Sampling was conducted in February, May, August and November 2006. Benthic samples were collected with a Van Veen Grab sampler from depths of 7 and 20 meters along two transects, from western parts of the coast to Radio Darya area at the east. In the present study, 4 species, 4 genera and 2 families of polychaetes were observed, which were dominated by Parhypania brevispinis. The average maximum density of polychaetes was 3644.2 individuals per square meter (with standard error of 872.1) during Summer in the depth of 7 meters of western transect, while a mean minimum density of 133.3 individuals per square meter (with standard error of 28.9) was observed during Winter in the depth of 7 meters in the same area. Maximum average biomass of polychaetes was 1900 mg per square meter (with standard error of 740) during Spring in the depth of 20 meter of Line 8 area, while the minimum biomass was 30 mg per square meter (standard error was 20) during Winter in the depth of 7 meter in the same area. Generally speaking, the western part of Chalus Coast had more density and biomass as compared with the eastern part.