Wildlife & Biodiversity

All 5 freshwater dolphins threatened, 31 species extinct: IUCN Red list

Over-harvesting, destructive fishing methods and introduction of predatory species among major reasons for increasing decline of 17 fish species endemic to Lake Lanao 

 
Published: Monday 14 December 2020

All five freshwater dolphins species — Ganga, Amazon, Indus, Irrawaddy and Tucuxi — are threatened with extinction, according to the latest update of the International Union for Conservation of Nature’s (IUCN) Red List of Threatened Species.

According to the update dated December 10, 2020:

“With the tucuxi (Sotalia fluviatilis) moving from ‘data deficient to ‘endangered’, all the world’s freshwater dolphin species are now listed as ‘threatened’ on the IUCN Red List. The small, grey dolphin species found in the Amazon river system has been severely depleted by incidental mortality in fishing gear, damming of rivers and pollution”. 

IUCN also declared 31 species as extinct through the update. They include:

  • 15 freshwater fish species endemic to Lake Lanao and its outlet in the Philippines
  • Three Central American frog species
  • Lost Shark (listed as critically endangered / possibly extinct)
  • Three Macadamia species of protea (a genus of South African flowering plants) family
  • Nine Asian oak species. 

“The Lost Shark was last recorded in 1934. Its habitat in the South China Sea has been extensively fished for more than a century; it remains one of the most overexploited marine regions in the world.

The Lost Shark may already be extinct as it is unlikely that the species could have persisted under this heavy pressure,"  the update stated. 

Over-harvesting, destructive fishing methods and introduction of predatory species were listed as the major reasons for 17 fish species endemic to Lake Lanao and its outlet in the Philippines becoming either ‘extinct’ (15) or ‘critically endangered’ (possibly extinct).

Among others declared newly extinct and critically endangered (possibly extinct) were three Central American frog species and 22 frog species across Central and South America respectively.

The main driver of these drastic declines, the update noted, was chytridiomycosis disease. Conservation efforts to protect critical habitat have, however, been populations of several other amphibian species to recover.

Among them is the Oaxaca Treefrog (Sarcohyla celata), which moved from ‘critically endangered’ to ‘near threatened’, owing to actions by local communities in Mexico.

Among plants, nine species of Oak trees have become extinct: They have been updated to critically endangered (possibly extinct or possibly extinct in the wild).

"The highest numbers of threatened species are in China and Mexico, followed by Vietnam, the United States and Malaysia. Land clearance for agriculture and logging are the most common threats in China, Mexico and Southeast Asia. Invasive alien species and diseases and climate change are the key threats to oaks in the United States,” the update said. 

The protea family, which includes three Macadamia species (that produce the farmed macadamia nut crop), have entered the IUCN Red List as threatened with extinction in the wild.

Subscribe to Weekly Newsletter :
Related Stories

Comments are moderated and will be published only after the site moderator’s approval. Please use a genuine email ID and provide your name. Selected comments may also be used in the ‘Letters’ section of the Down To Earth print edition.