Published: 20th Jan, 2020
One of the largest freshwater fish has been declared extinct in a study published in the journal Science of the Total Environment.
Context
One of the largest freshwater fish has been declared extinct in a study published in the journal Science of the Total Environment.
About
- The Chinese paddlefish (Psephurus gladius) was an iconic species, measuring up to 7 m in length, dating back from 200 million years ago, and therefore swimming the rivers when dinosaurs ruled the Earth.
- Its ancestral home was the Yangtze River.
- Chinese researchers made this conclusion based on the Red List criteria of the International Union for Conservation of Nature (IUCN).
The Red List has several categories for extinction
- “Extinct in the wild” means a species survives only in a captive environment
- “Locally extinct” means a species has ceased to exist in a particular area but may exist in other areas.
- “Functionally extinct”, which means the species continues to exist but it has too few members to enable to reproduce meaningfully enough to ensure survival.
- “Globally extinct”, it means a species has no surviving member anywhere. Such a conclusion is reached when there is no reasonable doubt left that its last member has died.
Other facts
- Declaring a species extinct is an elaborate process. It involves a series of exhaustive surveys, which need to be taken at appropriate times, throughout the species’ historic range and over a time-frame that is appropriate to the species’ life cycle and form.
- Once declared extinct, a species is not eligible for protective measures and conservation funding; therefore, the declaration has significant consequences.
- In the case of the Chinese paddlefish, the researchers made the conclusion over long-term surveys. It was once common in the Yangtze, before overfishing and habitat fragmentation — including dam building — caused its population to dwindle from the 1970s onwards.
- Between 1981 and 2003, there were just around 210 sightings of the fish.
- The researchers estimate that it became functionally extinct by 1993, and extinct sometime between 2005-2010
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