The bluefin tuna joined the Chinese pufferfish, American eel, Chinese cobra and Australian black grass-dart butterfly on the International Union for Conservation of Nature's (IUCN) "red list" of threatened species.
The updated list was released by the IUCN at its once-a-decade World Parks Congress in Sydney as it called for better management of protected areas, where some of the decline in species levels has taken place.
"But we have scientific evidence that protected areas can play a central role in reversing this trend," she added.
For this year's list, the IUCN assessed 76,199 species, with 22,413 judged to be under threat.
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The Pacific bluefin tuna moved from the "least concern" threat category to "vulnerable" as the species is threatened with extinction due to its use in Asia's sushi and sashimi markets, the Swiss-based group said.
It called for fisheries to implement conservation and management measures for the Western and Central Pacific Ocean.