Diversity of Clupeidae (Cuvier, 1816) in the New Calabar River, Rivers State, Nigeria

The study examined the diversity of Clupeidae species in the New Calabar River, Rivers State, Nigeria. Fish samples were collected monthly between May and October 2024 with the assistance of fishermen using various fishing gear. A total of 155 individuals belonging to the Clupeidae family were recovered and identified. Several ecological indices were applied to analyze species abundance and diversity. Five species were recorded: Pellonula leonensis, Ethmalosa fimbriata, Ilisha africana, Sardinella maderensis, and Sardinella aurita. The most abundant species was Sardinella maderensis (49.03%), followed by Ilisha africana (16.77%), while Ethmalosa fimbriata showed the lowest abundance (5.16%). The Simpson’s index peaked in September (0.73) and was lowest in August (0.08). Dominance was highest in August (0.92) and lowest in September (0.27). The Shannon-Wiener index reached its highest value in September (1.45), indicating a highly diverse community, and the lowest in August (0.19). The evenness index was highest in October (0.91) and lowest in August (0.61). Margalef’s index was highest in September (1.91) and lowest in August (0.31), suggesting reduced richness and fewer species relative to the number of individuals during that month. The diversity indices indicate that the family Clupeidae is fairly distributed in the study area. It is therefore recommended that further research be conducted to provide a comprehensive understanding of the biology and ecology of Clupeidae in the New Calabar River.