Yangtze finless porpoise

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.

Sand Mining:

• 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

Sources: DTE

Previous Year Question

Q1) Which one of the following is the national aquatic animal of India?  (2015)

1. Saltwater crocodile
2. Olive ridley turtle
3. Gangetic dolphin
4. Gharial