A research group from the International Union for Conservation of Nature (IUCN) has conducted the world's first comprehensive assessment of the habitats of over 2 freshwater fish species on a global scale. It has announced that a quarter of them are at risk of extinction. More than 3 researchers from Japan, including Professor Yoshinori Taniguchi of Meijo University and Professor Katsutoshi Watanabe of Kyoto University, participated in the assessment project.
Freshwater is an essential resource for human life and economic development, but the organisms that live there are constantly under great stress. Over 1,000 experts from around the world spent more than 20 years conducting the world's first comprehensive, global-scale, detailed survey of the habitats and conservation status of 2 species of freshwater fauna, including fish, crustaceans, and dragonflies.
As a result, it was found that about a quarter of the world's freshwater species assessed are at risk of extinction. The percentages were about 4% for arthropods such as shrimp and crabs, 1% for fish, and 30% for dragonflies. Since 26, more than 16 freshwater species have become extinct, and a further 1500 species are at risk of extinction. As the detailed distribution and habitat status of some species are unknown, it is highly likely that the figures are underestimated.
The causes cited include declining water levels due to climate change (global warming) and abnormal weather, excessive water withdrawal for agricultural and industrial purposes, unregulated fishing and overfishing for the sale of ornamental fish, dam development, pollution, and declines in populations due to predation and competition by invasive species, etc. Between 1970 and 2015 alone, approximately 35% of the world's wetlands, including swamps, marshes, and ponds, were lost, which is three times faster than the rate of forest loss.
Freshwater ecosystems are important habitats for freshwater organisms and also play an important role in regulating the climate, but in many cases they have been damaged and lost without being seen or even noticed. Preventing the decline and loss of species in the future is an urgent task, and will also help protect human life.
Paper information:【Nature】One-quarter of freshwater fauna threatened with extinction