In News: New research done in the Dongting lake in China that joins the Yangtze river found the cetaceans were pushed out of certain stretches of their habitat due to sand mining.
- This divides up the population and increases stress among the individuals, especially during pregnancy
- Gaps between porpoises in the lake reached 27 kilometres in 2009
Yangtze finless porpoise:
- IUCN status – critically endangered
- The Yangtze finless porpoise belongs to the group of animals which also includes dolphins and whales.
- It is the only freshwater porpoise in the world and breeds just once in 18 months.
- It is the most critically endangered of its taxonomic group and the species has an 86 per cent chance of becoming extinct in the next century.
- Yangtze River dolphin was lost
- The lake is connected to the main body of the Yangtze river by a channel that runs under the Dongting Lake Bridge.
- The porpoise population would swim to and from the river through this channel but because of sand mining, they were not seen in this channel any longer.
- Overfishing, increased shipping traffic and noise pollution have all been linked with the decline of the porpoise.
- Sand mining – mining activity posed multiple challenges to this endangered species.
- Sand mining was banned in the region in 2017
- Mining-induced loss of near-shore habitats, a critical foraging and nursery ground for the porpoise, occurred in nearly 70 per cent of the water channels
- Sand mining, which has tripled in the last two decades, is an emerging concern for global biodiversity – Over 50 billion tonnes of sand is mined every year.
- The menace is most rampant in Asia, Africa and Latin America.
- It threatens biodiversity and interferes with ecological processes through “direct physical disturbances, habitat degradation and reducing water quality by altering sedimentation
- Higher urbanisation has made sand the second-most extracted natural resource in the world after water.
- Checking sand mining can help the population of the Yangtze finless porpoise to rebound
Previous Year Question
Q1) Which one of the following is the national aquatic animal of India? (2015)
- Saltwater crocodile
- Olive ridley turtle
- Gangetic dolphin