Fish Diversity and Conservation in Freshwater Ecosystems

Freshwater ecosystems harbour an extraordinary array of fish species, ranging from minute crustacean feeders to large predatory catfish. These habitats—rivers, lakes, wetlands and streams—provide essential ecosystem services including nutrient cycling, water purification and support for human livelihoods through fisheries and aquaculture. However, global fish diversity is threatened by habitat fragmentation, pollution, water‐abstraction, invasive species and climate change. Fragmented riverine networks disrupt migratory pathways of diadromous and potamodromous species, while altered flow regimes and sediment dynamics degrade spawning grounds. Conservation efforts now integrate habitat restoration, legal protection of key reaches, community-led management and ex situ breeding programmes informed by conservation genetics. New approaches, such as environmental DNA surveys and longitudinal monitoring of ichthyoplankton, are enhancing our capacity to detect shifts in community composition. Effective strategies require collaboration among policymakers, local stakeholders and scientists to balance biodiversity conservation with sustainable resource use, thereby safeguarding the global significance of freshwater fish diversity and the services it underpins.

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Fish Diversity and Conservation in Freshwater Ecosystems publication trend

The graph below shows the total number of articles in fish diversity and conservation in freshwater ecosystems across all publications each year (not limited to Nature Index journals).

Technical terms

Ichthyoplankton: Fish eggs and larval stages drifting in aquatic environments.

Species richness: The total number of different species present in a defined area.

Species evenness: The relative abundance distribution among species within a community.

Diadromous: Fish species that migrate between freshwater and marine habitats during their life cycle.

Spawning grounds: Specific habitats where fish reproduce and release eggs.

References

1. A long-term ichthyoplankton monitoring program suggests climate-induced environmental variabilities changed fish communities in the Hudson River estuary. Frontiers in Marine Science (2023).
2. Ecological Insights, and Fin Fish Diversity in Carps Spawning Grounds: Case Studies from the Surma River and Tanguar Haor, Bangladesh. Scientifica (2024).
3. Indigenous Freshwater Ichthyofauna in the Dhanu River and Surrounding Wetlands of Bangladesh: Species Diversity, Availability, and Conservation Perspectives. Conservation (2021).