A Quarter of Freshwater Fish Species at High Risk of Extinction
Context:
A recent assessment conducted for the IUCN Red List of Threatened Species has revealed alarming findings about the state of freshwater biodiversity. Published in Nature Journal, the study highlights that 25% of freshwater species are under threat of extinction. This comprehensive analysis of 23,496 species of decapod crustaceans, fishes, and odonates provides a global overview of the challenges facing freshwater ecosystems.
Key Findings:
- 25% of studied species are classified as threatened with extinction, representing 4,294 species out of 23,496 analyzed.
- Freshwater ecosystems are rapidly losing species due to a combination of human activities and environmental changes.
Regional Hotspots:
Certain regions are more severely affected, with the highest number of threatened species found in:
- Lake Victoria
- Lake Titicaca
- Sri Lanka’s wet zone
- Western Ghats of India
These regions are globally recognized for their high freshwater biodiversity, hosting many species that are found nowhere else in the world.
Confirmed and Suspected Extinctions:
- A total of 89 species have been confirmed extinct, and an additional 178 species are suspected to have gone extinct since 1500.
- Most extinctions occurred in:
- USA: 22 species
- Mexico: 15 species
- Philippines: 15 species, all endemic to Lake Lanao
- 11 freshwater fish species exist only in captive populations, with 8 of these being native to Mexico.
The researchers noted that the actual number of extinctions is likely higher due to insufficient data and the existence of undescribed species that were not assessed.
Major Threats and Reasons for Freshwater Fish Extinction:
- Agriculture and invasive species are significant drivers of extinction, impacting both freshwater species and tetrapods.
- Specific threats unique to freshwater ecosystems:
- Pollution from agricultural runoff and industrial waste
- Dams, which disrupt natural water flow and habitats
- Water extraction for human use
- Overharvesting is also a prominent factor contributing to the decline of freshwater species.
Impact of Climate Change on Extinction:
- Direct effects:
- Changes in temperature and flow regimes
Importance of Freshwater Ecosystems:
Freshwater habitats are vital for both biodiversity and human well-being:
- They cover less than 1% of Earth’s surface but support:
- Over 10% of all known species
- Approximately 1/3 of vertebrates
- Nearly 1/2 of fishes
- They provide crucial ecosystem services, including:
- Nutrient cycling
- Flood control
- Climate change mitigation
- More frequent and severe weather events
- Indirect effects:
- Amplifying other threats, such as the spread of invasive species
- Increasing human demand for water resources
- Close to 20% of threatened freshwater species are directly affected by climate change and extreme weather events.
Way Forward: Steps to Arrest Freshwater Fish Decline
Steps to Address the Crisis
- Implement integrated conservation efforts that focus on both freshwater species and tetrapods.
- Address unique threats to freshwater ecosystems by:
- Reducing pollution through better agricultural and industrial practices.
- Reassessing and optimizing dam construction and water management.
- Controlling overharvesting of freshwater species.
- Strengthen climate adaptation measures to mitigate the impacts of temperature changes, altered water flows, and extreme weather.
Conclusion:
Upcoming Milestone: The 2025 IUCN World Conservation Congress, scheduled for October 9-15, 2025, in Abu Dhabi, presents a critical opportunity to guide global conservation strategies for the next four years. The Congress will align efforts with the Sustainable Development Goals (SDGs) and The Kunming-Montreal Global Biodiversity Framework targets for 2030.This platform is expected to catalyze urgent action to protect freshwater ecosystems, benefiting both nature and people.
