For this year's list, the IUCN assessed 76,199 species, with 22,413 judged to be under threat.
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.
As most of the fish caught are juveniles that have not yet reproduced, the population has dropped by 19-33 percent over the past 22 years.
It called for fisheries to implement conservation and management measures for the Western and Central Pacific Ocean.
The American eel is reeling from the impact of climate change, parasites, pollution, habitat loss and commercial harvesting, as well as having been hit by the high levels of consumption of its counterpart, the Japanese eel.
The IUCN categorised the Chinese cobra as "vulnerable" with the population falling 30-50 percent over the past two decades -- another species hurt by its popularity as a food source.
"The growing food market is putting unsustainable pressure on these and other species," the IUCN's biodiversity head Jane Smart said.