Dolphins swarm video: San Diego mega pod of dolphins spotted off California coast

SAN DIEGO - A Valentine's Day whale-watching excursion turned into a rare treat off the San Diego coast as an estimated 100,000 dolphins swarmed offshore, according to one boat captain.

Captain Joe Dutra was at the helm of the Hornblower Adventurer when he spotted what he called a "spectacular event." 

Dutra said the dolphin pod stretched 7 miles long and 5 miles wide. 

"It was like nothing I've ever seen," he told 10News reporter Allison Ash.

Dutra said even when he sailed on fishing boats off South America – where dolphin pods are common – he has never seen anything this huge.

Because the sighting was so rare and the waters were relatively calm, Dutra opened up the front of the boat so spectators could get a better view. 

For more than an hour, the tourists onboard "ooh'd" and "aah'd" and snapped photos.

10News contacted a marine life expert who said the mega-pod was likely the result of food in the area. Dolphins often go where the food is, so it may have been a gigantic feeding frenzy.

It was a frenzy that did not repeat itself. Several whale-watching cruises have passed through the same area since the sighting, but the dolphins were nowhere to be seen.