Fish Species Composition and Abundance in the Hadejia-Nguru Wetlands, Jigawa State

This study documented the fish species composition and seasonal abundance in the Hadejia-Nguru Wetlands, located across Jigawa and Yobe states, with primary fieldwork conducted in the Jigawa section. The Hadejia-Nguru Wetlands represent one of West Africa's most significant Ramsar sites, supporting extensive pastoral, agricultural, and fisheries activities for millions of people. Fish samples were collected using traditional fishing methods including basket traps, long lines, and drag nets in collaboration with local fishers at six wetland sites over a period encompassing both flooding and recession seasons. Specimens were identified using morphological keys appropriate for the Sahel-Sudan freshwater fish fauna. A total of 24 species from 13 families were recorded, with Cichlidae, Mochokidae, and Alestidae being the most species-rich families. Oreochromis niloticus, Clarias gariepinus, and Synodontis membranaceus were the most abundant species by catch weight across both seasons. Species richness and abundance were significantly higher during the flooding season when fish dispersed into the flooded floodplain to feed and breed. Connectivity between the main river channel and flood pools was identified as a critical driver of productivity. Declining river inflow attributable to upstream water extraction for irrigation was identified as the primary long-term threat to wetland fisheries productivity. The study recommends the adoption of minimum environmental flow standards for upstream dams to sustain the ecological productivity of the Hadejia-Nguru Wetlands fisheries. Keywords: Hadejia-Nguru Wetlands, fish diversity, seasonal abundance, freshwater fisheries, Jigawa State