Watch: Pod of killer whales trapped in drift ice off Japan coast

What happened: A fisherman reportedly spotted the orcas about 1 kilometer (0.62 miles) from the coast of Rausu, a town in Hokkaido, on Tuesday morning. He reported his discovery to town officials shortly after.

Drone footage captured by a conservationist group shows about a dozen orcas — including a baby — bobbing up and down as they struggled to breathe while being trapped in a narrow space enclosed by the ice. Unlike other large whales, orcas need to resurface from time to time to breathe.

Call to action: Japanese citizens raised concerns after seeing the video broadcasted on NHK and shared on social media. One group submitted a request for authorities to deploy an ice breaker to help the trapped marine mammals.

How authorities responded: Rausu officials reportedly went to the scene on Tuesday evening to monitor the orcas, which they confirmed were still trapped at the time. They said they could not carry a rescue operation as their vessels were unable to go through the blocked spaces between the drift ice.

The officials, however, returned on Wednesday and found that the orcas had disappeared. “As the gap in the drift ice started to open, it’s likely they escaped,” an official told Reuters.

Not the first time: A similar incident reportedly occurred in the area in 2005. At the time, nearly a dozen orcas were trapped inside drift ice, resulting in several deaths.