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Marine Science

ON WORLD RIVER DOLPHIN DAY WWF SHOWCASES FIVE REMAINING SPECIES

On World River Dolphin Day WWF showcases five remaining species

WWF’s River Dolphin River Initiative includes new Amazon river dolphin dashboard, collating two decades of population surveys and tagging

On World River Dolphin Day, conservation group WWF is revealing the latest measures to better understand and protect this iconic mammal.  With only five species of river dolphins left in the world, all of which are endangered or critically endangered, securing a future for them is crucial.  One innovation that’s been developed is a dashboard for the Amazon species, which brings together all available data for the first time.

The need for this and other initiatives was made clear in WWF’s Living Planet Report, which shows average population trends for monitored freshwater species has fallen steeply with an 84% decline in fifty years.  Large animals such as river dolphins are particularly at risk, with an 88% drop in populations.1

Dave Tickner, Chief Freshwater Adviser at WWF-UK said: 

“River dolphins are flagships for the health of the world’s great rivers, but they are vulnerable to the huge changes we are making to their environment, so they need better global protection to secure their long-term future.

“WWF’s Living Planet Report 2020 shows the catastrophic loss of freshwater wildlife is happening over twice as fast as on land, or in our oceans, with a more than a quarter of species heading for extinction.”

WWF has devised two complementary plans that can help halt and reverse the decline in river dolphin populations: the six-point Emergency Recovery Plan for global freshwater biodiversity and the River Dolphin River Initiative which is aiming to double the most threatened populations by 2030.

The main threats to river dolphins are:

  • Unsustainable fishing and fishing-related activities.In Asia, illegal bycatch is the number one cause of riverdolphin deaths. In South America, intentional killing of river dolphins for fish bait and meat affects several thousand dolphins a year.
  • Infrastructure projects that affect habitat connectivity,including hydropower dams, irrigation barrages andembankments. In Asia, river dolphin habitat has decreased by 50 -70% and by 10% in South America, where hundreds of new dams are planned.
  • Mining, agriculture, deforestationand industrial developmentall degrade water quality, which is a serious threat to dolphins. Mercury poisoning from illegal gold mining has been found in dolphins in Asia and South America.

The pink Amazon River dolphin, known as the “Boto” is found in the Amazon and Orinoco River Basins, but populations are increasingly under threat.  WWF and its partners in SARDI (South American River Dolphin Initiative) are using innovative techniques such as drones and satellite tagging to count populations of the “Boto” and its smaller, grey cousin, the Tucuxi. The coalition’s new interactive dashboard tool collates two decades of river dolphin population surveys combined with two years of dolphin tagging from across the region.

Marcelo Oliveira, river dolphin conservation specialist at WWF Brazil said:

“This is the culmination of a huge collaborative effort to count river dolphins using drones and tagged individuals, to determine how many remain and how they live.

“The dashboard will be a vital tool to inform conservation and planning decisions, to better protect the Boto and Tucuxi and help populations to recover. However, we need governments to act to reverse and halt hydropower dams and to end illegal gold mining.”

The global efforts to protect river dolphins are being driven by a desire to avoid the five remaining species meeting the same fate as that of the Yangtze river dolphin, known as the Baiji, which was last seen eighteen years ago and has been declared “functionally extinct.” The Yangtze is also home to the Yangtze finless porpoise, of which there are only around a thousand remaining.

The South Asian river dolphin consists of two sub-species, the Ganges and Indus River dolphins. Estimates put the Ganges River dolphin population between twelve and eighteen hundred, the majority of which are found in India with less than a hundred in Nepal, where it is a protected species. 2 The Ganges River dolphin is essentially blind and relies on echolocation. There are less than two thousand  Indus River dolphins left in the world and they exist in isolated populations, confined to a short stretch of the river due to the construction of major irrigation systems.

One of the most threatened river dolphin species is the Irrawaddy river dolphin, with fewer than 300 remaining in three isolated populations in the Irrawaddy (Myanmar), Mahakam (Indonesia) and the Mekong (Cambodia) Rivers. According to WWF’s Living Planet Report 2020, the population in the Mekong has plummeted by 44% since 1997.

Kathy Hughes, Freshwater Specialist at WWF-UK said: 

The Irrawaddy river dolphin holds a unique relationship with the fishing communities along the Irrawaddy by co-operating with them to catch fish; squirting jets of water to herd the fish into the nets. The dolphins are then rewarded by the fishermen by receiving a share of the catch.  

“The population of this intelligent and charismatic species in the Irrawaddy is Critically Endangered with fewer than 80 individuals. Every effort must be made through the Emergency Recovery Plan and River Dolphin Initiative to prevent this species from becoming extinct like the Yangtze river dolphin.”