STOCKHOLM (AP) — Researchers at an international water conference in Stockholm said that 21 percent of freshwater species in northern Africa are threatened with extinction.

Scientists from the International Union for Conservation of Nature presented a new report on Tuesday, which shows more than 1,000 fish, crabs, mollusks, aquatic plants and insects in northern Africa are in danger.

The IUCN said agriculture, water abstraction and dams are the biggest threats to these species, and urged governments to better manage their water resources.

The report summarizes the findings of 200 scientists, who had worked for five years to assess a total of 5,167 African freshwater species.