The Relationship between Salinity and Benthic Fauna Diversity and Abundance at Songkhla Port, Thailand

Abstract

Benthic fauna plays an important role in marine ecosystems as the primary food for other aquatic animals, and this animal group helps reduce sediment nutrients by filter feeding. The aim of this study was to evaluate and explain the diversity and abundance of the benthic fauna community at the Songkhla port, where both human activities and environmental fluctuations affect this community. Benthic fauna and water samples were collected at 2-month intervals from January to November 2017. The results show that most physical parameters had wide ranges and varied by month. The benthic fauna in the Songkhla lagoon was observed in this study. The results showed a higher number of taxa compared with a previous study. Three phyla, namely, Annelida, Arthropoda, and Mollusca, had 25 taxa recorded in this study. Crustaceans were the most diverse (nine taxa) and abundant (2981 6 313 ind/m 2 ) group, followed by polychaetes (eight families, 2350 6 288 ind/m 2 ) and mollusks (eight taxa, 633 6 200 ind/m 2 ). Barnacles were the dominant group of crustaceans (2153 6 758 ind/m 2 ), whereas Serpulidae (1864 6 647 ind/m 2 ) and Mytilidae (447 6 367 ind/m 2 ) were the dominant families of polychaetes and mollusks, respectively. Cluster analysis showed that the distribution of benthic fauna and physicochemical water quality varied with similar patterns. Clustering gave two groups: for rainy season from November to January and for dry season from May to November. According to canonical correspondence analysis, salinity and transparency were the main environmental factors associated with the distribution pattern of benthic fauna in the area. In conclusion, the activities at the Songkhla port have not yet created problems for marine benthic fauna; instead, seasonal changes appear to drive changes in benthic fauna. However, future construction developments can affect the geographical area, complementing stresses from parameter changes at local scales.

A new species of the genus Ctenapseudes Bamber, Ariyananda et Silva, 1997 (Tanaidacea: Parapseudidae) from the Cần Giờ mangrove area in South Vietnam

“…The abundance of these opportunistic feeders usually indicates a significant accumulation of organic matter in the area [Pearson, Rosenberg, 1978]. For example, Ctenapseudes sapensis is the dominant species widespread in the Songkhla Lagoon, Thailand, reaching its peak density of 5,044 inds/m 2 in the period following the rainy season (February) [Angsupanich, Siripech, 2001;Jombodin et al, 2022]. This species is a major food source for the locally dominant ariid catfishes, Osteogeneiosus militaris (Linnaeus, 1758) and Arius maculatus (Thunberg, 1792) (Siluriformes: Ariidae) [Angsupanich et al, 2005b].…”