The Selwyn River, also known as Waikirikiri, is a significant waterway flowing approximately 80 kilometers across the patchwork farmland of the Canterbury Plains before entering Lake Ellesmere. This river system presents a diverse angling environment, transitioning from its headwaters through the Selwyn Gorge and across the plains. It is a notable fishery within the Selwyn District, offering opportunities for both resident and migratory fish species, though its character and fishability are heavily influenced by seasonal flow patterns and specific regional regulations.