Abundance of Macrobenthos in Seagrass Beds at Khao Meng, Maifad Subdistrict, Sikao District, Trang Province

Abstract

This research investigated the abundance of macrobenthos within the seagrass beds of Khao Meng, Maifad Subdistrict, Sikao District, Trang Province. Macrobenthos samples were collected during two seasons: dry and the Southwest monsoon seasons. Three fixed sampling stations were established 200 meters apart. At each station, samples were collected along three transects located at 0 meters, 100 meters, and 200 meters from the highest tide line. A 0. 25 m² quadrat was used at each sampling point to collect macrobenthos samples from a total area of 1 m². The samples were sieved through a 1-mm sieve to separate macrobenthos from the sediment. Soil and macrobenthos samples collected from the same area were analyzed for organic matter content and particle size distribution. The study found minimal seasonal variation in the average soil pH ranged from 7.8 to 8.8. Organic matter content in the soil exhibited minimal variation across all stations and seasons, remaining consistently low ( 3. 95 ± 0. 04 to 4. 04 ± 0. 05 % ) . The most frequent sediment particle size fraction at all sampling points ranged between 0. 15 and 0. 25 mm. Fourteen polychaete families were identified in the Khao Meng seagrass beds: Arabellidae, Arenicolidae, Capitellidae, Eunicidae, Glyceridae, Goniadidae, Lumbrineridae, Maldanidae, Marphysa, Nereididae, Onuphidae, Orbiniidae, Oweniidae, and Trichobranchidae. Additionally, mollusks from two families (Potamididae and Nassariidae) and a single brachyuran crab family (Matutidae) were found.