Competitional settlement of brown alga Iyengaria stellata and soft coral Zoanthous sansibaricus on muddy and muddy-rubble intertidal substrate in the Hormuz island

The effect of substrates on the surface cover by the soft coral, Zoanthus sansibaricus, and the brown alga, Iyengaria stellata, and their competitional condition, was compared in Hormuz Island by estimating of coverage area in 40 quadrates (50×50 cm). This soft coarl (Zoanthid) is a dominant species in the island’s intertidal zone and I. stellata is a dominant macroalgea most of the year. Significant negative correlation (p<0.01; r =-0.607) revealed competition between the two species for settlement on the two substrates. Soft coral with 61.7% coverage was dominant vs. 16.8% for brown algae on muddy-rubble substrate, but on sandy-rubble substrate, the brown algae was dominant with 37.8% coverage vs. 19.5% for the soft coral. It seems that better competitional conditions in settlement on unconsolidated substrate have some advantages for Z. sansibaricus

A study on the diversity of gastropods in Hormuz Island with first record of two species from the Iranian coast of the Persian Gulf

This study was carried out to determine the diversity of gastropod species in the intertidal zone of Hormuz Island in the Persian Gulf. Seasonal sampling was conducted in 7 selected sites by throwing nine random quadrates (0.5×0.5 m) in each site. Samples of each site were separately transferred to the laboratory and identified by the standard keys and verified by the Conchology Museum of Tokyo University of Science. Forty -nine gastropod species were identified, from which 2 species, Turicula nelliae and Linatella caudata were recorded for the first time from the Iranian coast of the Persian Gulf. The highest number of gastropods in one site was 28 species in site 1 (East of Marine Research Center), Also highest number of gastropods in one season was 35 species in winter and lowest number was in 28 species in summer. Simpson dominance index, Shannon-Wiener species diversity index, Margalef richness index and evenness index were calculated in the different sites and results showed that site 1 contained the most amount of the Shannon-Wiener and Margalef indices and site 6 (West of Island) contained the most amount of the Simpson index. Also, site 3 (Mangrove forest) showed the lowest amount of the Simpson, Shannon-Wiener and Margalef indices, while maximum amount of evenness index occurred in this site