Abundance and Species Richness of Intertidal Gastropods in Qeshm Island, the Persian Gulf, Before and After Cyclone Gonu (2007-2008)

The present study was conducted to investigate the effects of cyclone Gonu on species diversity and abundance of gastropods in the Qeshm Island, northern Persian Gulf, on the occasion of the occurrence of super cyclonic and strongest reported storm- Gonu- during 1-4, June 2007 in the eastern Arabian Sea. Samples were collected before the Gonu storm (late May and early June 2007) and twice after the storm (July and August 2007 and March and April 2008). Average number of gastropod individuals per square meter was 7.85±1.42, 4.52±0.63, and 2.53±0.59 for rocky shores and 1±0.56, 0.11±0.06 and 4.26±3.96 for sandy shores, respectively. Both Shannon index and Buzas and Gibson's evenness measure increased after the storm suggesting that Gonu affected diversity of gastropods of intertidal zone. Unlike result of cluster analysis that depicted two distinctive groups of assemblages over the sampling periods before and after the storm in rocky shore, the result of Kruskal-Wallis test yielded no significant difference (P>0.05) in gastropod abundance among sampling periods in two locations. Results of the present study suggested that gastropods abundance was not significantly (P>0.05) affected by cyclone Gonu while the species diversity was influenced.