The beached whales were discovered by a helicopter pilot during a sightseeing tour in Iceland on Tuesday

Dozens of dead pilot whales washed up on an Icelandic beach were spotted by a sightseeing helicopter tour on Tuesday, and officials are unclear as to how the mammals became beached.

According to the BBC, helicopter pilot David Schwarzhans was taking a group of sightseers over a secluded beach in Longufjorur when they found the beached whales. Police in the nearby town of Stykkisholmur were notified of the situation after the tragic sighting.

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“We were flying northbound over the beach and then we saw them. We were circling over it not sure if it was whales, seals or dolphins. We landed and counted about 60, but there must have been more because there were fins sticking out of the sand,” Schwarzhans told the BBC.

“It was tragic and when we stood downwind it was smelly. It wasn’t something nice to see and quite shocking since there were so many”.

Marine biologist and whale expert Edda Elisabet Magnusdottir told the Iceland Monitor that when the whales enter shallow waters, “most of them have a tendency to become disorientated,” adding that pilot whales tend to swim in groups, which explains the number of beached whales located on the beach in western Iceland.

“The most important thing to look at is that these are deep-sea whales, common at the continental margin,” Edda told the news outlet. “They mainly feed on squid, which is why they’re good at diving deep. When they enter shallow waters, most of them have a tendency to become disoriented.”

“They use echolocation for orientation, for finding one another, estimating the depth, and so on. But a sloping, sandy bottom appears to increase their disorientation. There are numerous examples of them having beached where there is such a sandy, sloping bottom.”

The phenomena is hardly new, with nearly 145 pilot whales beached on a New Zealand island last year. Half of the whales were already dead upon being discovered, and the surviving mammals were put down.