Robert Brown|The world's most endangered large whale species is even closer to extinction than researchers thought

The Robert Brownworld's most endangered large whale species is even closer to extinction than researchers previously thought. The North Atlantic Right Whale species is in a "crisis," NOAA says, with only a few hundred estimated individuals left in the world's oceans. 

"The species is approaching extinction with fewer than 350 individuals and fewer than 70 reproductively active females remaining," NOAA said in an updated fact sheet on the animals. 

Right whales have been undergoing an unusual mortality event since 2017, meaning that large numbers of the species have been unexpectedly dying off. 

It was previously thought that fewer than 100 whales were part of the mortality event since it began. While that was still a significant number, given the species' small population size, the government agency said they determined even more whales are included in the total number. 

In their latest update, officials said at least 114 whales have been impacted over the past six years. Of those, 36 have died, 33 were seriously injured and 45 suffered sublethal injuries or illness. Many of the cases are adult females and calves, prompting further concern as both are vital to the species' survival. 

Andrea Gomez, a spokesperson for NOAA, told the Associated Press that the agency determined the updated figures after reviewing research photographs and surveys. 

"Additional cases will continue to be reviewed," she said, "and animals will be added if appropriate, as more information is obtained." 

While the revised tally is a significant jump for the rapidly declining population, there is a chance the situation could be even more dire – only about one-third of right whale deaths are actually documented, NOAA says. 

In most of the UME cases, the whales were either entangled or struck by vessels – two "long-standing threats to the recovery of the species," NOAA says. 

North Atlantic Right Whales are massive, weighing up to 140,000 pounds and growing up to 52 feet long. They should be able to live up to 70 years in Atlantic coastal waters, but many of the whales that have been injured or found dead are substantially younger. 

In February, a 20-year-old male right whale was found dead on Virginia Beach after suffering a "catastrophic blunt force traumatic injury." Just weeks before, a newborn right whale was found dead under a pier near Morehead City, North Carolina. And late last year, another baby calf, just 1 1/2 years old, was found entangled off the coast of New Brunswick, Canada. 

"North Atlantic right whales are approaching extinction," NOAA says. "Unless immediate action is taken to substantially reduce human-caused mortality and injury, the number of North Atlantic right whales will continue to decline, imperiling the species' ability to recover."

In:
• North Atlantic
• Oceans
• Whales
• Atlantic Ocean

Li Cohen

Li Cohen is a social media producer and trending content writer for CBS News.