بررسي فراواني و پراكنش پرتاران در سواحل صخره اي جزيره هرمز در خليج فارس

Survey of abundance and distribution of rocky shore Polychaeta from the Hormouz Island in Persian Gulf

Polychaeta are the most important benthic animals and consist of many species with a vital role in food web. We conducted a survey from summer 2005 to spring 2006 to complete the ecological studies of macrobenthos in rocky shores of the intertidal zone of the Hormouz Island. Three main regions were studied in the west, south and south-eastern parts and three transects were sampled in each region to test variation in Polychaeta distribution and abundance along the entire intertidal zone. At each one of the nine transects the shore was levelled and a general qualitative description was made, which also aided in the stratification of subsequent quantitative sampling. Samples were fixed in %4 formalin and transported to lab for analysis. Results showed presence of 10 genera of Polychaeta among which Nereis was the most abundant in the intertidal rocky shores. Our study also revealed seasonal and zonal distribution of Polychaeta in rocky shores of the area. Abundance of Polychaeta was markedly higher in summer compared to winter and in the upper zone compared with the mid- littoral zone. Results of Shannon and Simpson diversity indexes affirmed above conclusion.