At least 100 pilot whales have died so far after beaching themselves on the shores of New Zealand’s South Island on Friday, according to media reports. Rescue workers are racing against time as they wait for high tide to refloat the remaining whales.

“This is a big stranding. It's a real challenge,” Andrew Lamason of New Zealand’s Department of Conservation said, according to a report by The New Zealand Herald, adding that the rescue workers were readying themselves for the possibility that the whales might have to be put down to ease the suffering.

However, Lamason added, they were a long way from giving up. “We'll just keep on trying,” he reportedly said. As of now, rescue workers and a team of volunteers are trying to keep the whales hydrated by pouring water over them.

Nearly 200 pilot whales, which can grow to a length of up to 20 feet, had stranded themselves on Friday at Farewell Spit, Golden Bay -- a spot that has recorded several whale beachings in the past. However, local conservationists reportedly said that Friday’s incident was perhaps the biggest beaching incident in over a decade.

“It's a big, shallow hook. Whales come in, they get disoriented, and unfortunately we end up with a lot of dead whales,” Lamason reportedly said.

Once the whales get beached, they can suffer from severe dehydration and sunburn, resulting in severe physical and emotional trauma, according to media reports.

“Because there's just so many whales, there are a couple of spots where a lot would gather together and that's kind of problematic from the aspect that you can't get in there, it's just too dangerous,” Mike Ogle, a local ranger, reportedly said.

Although the exact cause of whales getting stranded is not yet known, some scientists have suggested that low- and mid-frequency sonar used by military ships might be interfering with the mammals’ echo-location system, disorienting them and hindering their ability to navigate.

“Another theory points to pilot whales’ highly sociable behavior -- when one whale loses its way and strands, its pod mates may swim to its aid,” New Zealand’s Department of Conservation said in a statement published on its website.