Review on Fish as Bio-Indicators: Assessing the Health of River Ecosystems

Fish are crucial for maintaining the ecological balance of river ecosystems, serving important functions in nutrient cycling, energy transfer, and habitat formation. As key components of intricate food webs, fish help control prey populations and uphold ecosystem stability. Their movements facilitate the distribution of nutrients throughout river systems, which supports primary productivity and enhances the connections between freshwater, estuarine, and marine environments. Moreover, fish serve as bio-indicators, signaling changes in water quality and habitat health due to pollution and environmental stress. This chapter explores the various roles fish play in preserving river biodiversity and ecological stability, with a focus on the impacts of human-induced challenges like overfishing, habitat destruction, and pollution. It emphasizes the critical need for effective conservation and management strategies to safeguard fish populations and their habitats, ultimately supporting the resilience and functionality of river systems.