A STUDY ON DISTRIBUTION AND BIOMASS ESTIMINATION OF SEAWEEDS IN COASTAL AND ITS ISLANDS

Document Type : Research Paper

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Abstract

Distribution and biomass of seaweeds in the Persian Gulf and its islands were assessed monthly during low tide from July 2001 to August 2003. Ten stations were defined in the study area and random spots along a transect vertical to the coastline were selected to carry out the sampling. Six stations were located in the coastal waters and four others were close to the islands. Samples were taken in quadrats 0.25 square meter in size (0.5mx0.5m). As a result, 77 species belonging to 4 division of seaweeds were identified. Rhodophyta was represented by 38 species, Chlorophyta had 21 species followed by 17 species of Phaeophyta and only 1 species of Cyanophyta. The highest and lowest seaweed diversity was seen around Larak Island and Michael station with 74 and 31 species respectively. Although some species such as Gracilaria corticata, Gelidiella acerosa, Laurencia snyderia, Colpomenia sinousa, Padina australis and Dictyosphaeria covernosa were abundant in all stations during the study, some species were absent from some stations. Thrbinaria conoiedes was only seen in Larak island, Spatoglassum variable and Steochospermum marginatum were present only in Larak and Qeshem islands, Codium papilatum and Ulva spp. were spotted only in Larak and Hormoz islands, and Sargassum ilicifolium was detected only in Bandar Lengeh, Shiyo, Larak and Qeshem islands. The maximum and minimum algal biomass (wet weight) was recorded in Bandar Lengeh with 1058gr.m-2 and Qeshem island with 391gr.m-2 and there was significant difference between the two stations (P<0.05). Also, the maximum algal biomass was recorded in summer (l466 gr.m-2) in Tahoneh Gorzeh and the minimum biomass (130 gr.m-2) in Qeshem islands. The highest biomass was recorded for the brown algae division (824 gr.m-2) in Bandar Lengeh and the minimum biomass was seen for the green algae division (26 gr.m-2) in Hormoz and Qeshm islands. The maximum biomass was 755gr.m- in summer for red algae, 1160gr.m-2 in Spring for brown algae and 5l9gr.m-2 in Summer for green algae.

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