Keanekaragaman Nekton di Muara Sungai Kelurahan Pulau Sicanang Belawan Sumatera Utara

Abstract

The Sicanang Island Village Estuary in Belawan, North Sumatra, is a vital ecosystem for nekton, yet vulnerable to anthropogenic degradation. This study, aimed to analyze nekton diversity and its influencing environmental factors. Nekton samples were collected from three stations using cast nets, traps, and fishing rods, followed by species identification and in situ water quality parameter measurements. A total of 36 nekton species (23 families and 36 species) were identified, comprising 3,349 individuals. The diversity index (H') was moderate (1.78-2.05); abundance was highest (1,417 individuals) at the mangrove station (Station II) and lowest (895 individuals) at the industrial station (Station I). Penaeus indicus showed the highest relative abundance (28.45% at Station III). The evenness index (E) was high (0.72-0.82), and dominance (C) was low (0.17-0.26). Water quality indicated acidic pH (6.2-6.6) and DO below standard quality (4.46- 4.63 mg/L). The PCA analysis indicated that brightness, pH, and salinity are positively correlated with nekton diversity, whereas temperature and dissolved oxygen (DO) exhibit negative correlations. Dissolved oxygen (DO) demonstrated a very strong negative correlation (-0.991) and emerged as the most significant factor. In conclusion, nekton diversity in the Sicanang Island Village Estuary is moderate, with Dissolved Oxygen (DO) being the primary environmental factor negatively affecting it.