MONTREAL, Canada, Dec. 9 (Xinhua) -- Two populations of a large herbivorous marine mammal, numerous shellfish species of abalone and a hard coral found in the Caribbean Sea are now threatened with extinction, the International Union for Conservation of Nature (IUCN) announced Friday.

In total, more than 1,550 of the 17,903 marine animals and plants assessed are at risk of extinction, with climate change impacting at least 41 percent of threatened marine species, according to the IUCN's updated Red List of Threatened Species.

The IUCN's updated Red List, released at the UN biodiversity conference known as COP15 in Montreal, now includes 150,388 species, of which 42,108 are threatened with extinction.

IUCN Director General Bruno Oberle said in a statement that the IUCN Red List update reveals a perfect storm of unsustainable human activity decimating marine life around the globe.

"As the world looks to the ongoing UN biodiversity conference to set the course for nature recovery, we simply cannot afford to fail," said Oberle.

"We urgently need to address the linked climate and biodiversity crises, with profound changes to our economic systems, or we risk losing the crucial benefits the oceans provide us with."

The IUCN found that populations of dugongs in East Africa and New Caledonia are deemed as critically endangered and endangered respectively, although the species remains vulnerable globally.

There are fewer than 250 mature individuals in East Africa and under 900 in New Caledonia, it said, noting that the primary threats are unintentional capture in fishing gear in East Africa and poaching in New Caledonia, and boat injuries in both locations.

The species also suffers from the loss of seagrasses that they depend on for food. Meanwhile, the impacts of climate change present a threat throughout the animal's wide range, it added.

"Strengthening community-led fisheries governance and expanding work opportunities beyond fishing are key in East Africa, where marine ecosystems are fundamental to people's food security and livelihoods," said Evan Trotzuk, who led the East Africa Red List assessment.

The IUCN's Red List also assessed abalone species for the first time and found 44 percent of all abalone species -- 20 of 54 -- are now threatened with extinction.

Abalone species are sold as some of the world's most expensive seafood, and the primary threats are unsustainable extraction and poaching, compounded by climate change, disease and pollution, the IUCN said.

For example, increasingly frequent and severe marine heatwaves have caused mass mortalities, killing 99 percent of Roe's abalones in its most northerly reaches of Western Australia in 2011. Marine heatwaves also kill the algae that abalones depend on for food.

The pillar coral, found throughout the Caribbean, has moved from vulnerable to critically endangered, according to the IUCN, after its population has shrunk by over 80 percent across most of its range since 1990.

The most urgent threat is Stony Coral Tissue Loss Disease, which has emerged in the past four years and is highly contagious, infecting between 90 and 100 meters of reef per day.

"The awful status of these species should shock us and engage us for urgent action," said Professor Amanda Vincent, chair of the IUCN's Marine Conservation Committee.

"These magical marine species are treasured wildlife, from the wonderful abalone to the charismatic dugong and the glorious pillar coral, and we should safeguard them accordingly. It is vital that we manage fisheries properly, constrain climate change and reverse habitat degradation," Vincent added.