Biodiversitas Ikan di Pantai Mangrove Desa Sei Naga Lawan Kecamatan Perbaungan Kabupaten Serdang Bedagai Provinsi Sumatera Utara

Abstract

The mangrove coastal area of Sei Naga Lawan Village is one of the coastal ecosystems in Serdang Bedagai Regency that has considerable fish resource potential but is increasingly subjected to environmental pressures due to human activities and changes in water quality. This study aimed to determine fish biodiversity and analyze the relationship between physicochemical water parameters and fish community structure in the mangrove coastal waters of Sei Naga Lawan Village. The research was conducted from July to August 2025 using a field survey method at three sampling stations determined by random purposive sampling. Fish samples were collected using hand lines, fish traps, and gill nets, while water quality parameters measured included temperature, water transparency, depth, pH, dissolved oxygen (DO), and salinity. Data analysis consisted of relative abundance, diversity index (H’), evenness index (E), dominance index (C), and Principal Component Analysis (PCA). The results showed that a total of 25 fish species belonging to two classes, Actinopterygii and Chondrichthyes, were recorded during the study. The species with the highest relative abundance at all sampling stations were Johnius carouna and Johnius trachycephalus. The diversity index values at the three stations were classified as low, ranging from 1.17 to 1.32, while the evenness index ranged from low to moderate (0.43–0.48), and the dominance index was categorized as low (0.40–0.44). Water quality parameters indicated that temperature and salinity were within the tolerance range for marine biota; however, pH and dissolved oxygen levels were below the established marine water quality standards. PCA results revealed that physicochemical parameters, particularly temperature, depth, and dissolved oxygen, were associated with fish abundance and biodiversity patterns. This study provides essential baseline information to support sustainable management and conservation of fish resources in the mangrove coastal area of Sei Naga Lawan Village.