Assessing Invasive Fish Diversity in Lake Ranu Grati, Indonesia

This study analyzed invasive fish species diversity in Lake Ranu Grati, Pasuruan, East Java. Sampling occurred at four stations using cast nets. Community structure was evaluated using Shannon–Wiener diversity (H'), uniformity (E), dominance (C), density (D), and relative abundance (KR). Results revealed 88 individuals across four species: Louhan (Amphilophus sp.), Tilapia (Oreochromis niloticus), Jaguar Cichlid (Parachromis managuensis), and Red Devil (Amphilophus labiatus). Values ranged for H' (0.96–1.14, low–medium), E (0.69–0.82, high), and C (0.39–0.45, low). Density peaked in vegetation areas (0.47 ind/m²) and was lowest in open water (0.10 ind/m²), showing a clumped pattern. Louhan dominated all stations (KR=55.56–63.64%). Habitat complexity and anthropogenic activity strongly influence these distribution patterns.