Catalina Channel swimmers this season are facing historically low water temperatures (sub-59°F or 15°C in many cases) and a growing number of shark sightings at various points, but they are also potentially treated to other unusual sights en route between Santa Catalina Island and the California mainland: the largest creatures on Earth, the blue whales.

An unusually large number of blue whales off the Southern California coastline is providing swimmers and crews with opportunities to see these magnificent mammals – up to 30 meters in length – as well as fin whales – up close.

“A year ago, we were lucky to see three or four blue whales per [whale-watching] trip,” said Michelle Sousa, senior biologist at the Aquarium of the Pacific, to the Los Angeles Times. “Now we’re seeing up to 15 per trip, along with a few fin whales thrown in for good measure.”

Photo by the National Oceanic & Atmospheric Administration shows one blue whale off the Southern California coast.

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