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If you go swimming in the ocean at night on Vancouver Island during the summer, you may be lucky enough to experience the magic of bioluminescent organisms.

“The bioluminescence looks like 100 sparks or glitter around your paddle stroke or around your arm as you swim through. It’s not one big, solid light. It’s lots of tiny, little lights,” said EJ Frederiksen, owner and manager of Pacifica Paddle Sports in Brentwood Bay.

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The bioluminescent glow is consistently visible in the Saanich Inlet near Brentwood Bay between May and October, said Frederiksen, who offers kayak tours three evenings a week to observe the phenomenon.

“The bay is calm and dark until you put your paddle in the water and then it lights up,” she said.

The bay’s warm, sheltered waters and dark shoreline provide ideal conditions for seeing a trail of glitter in the water as a paddle passes through, she said.

Although many organisms can emit bioluminescence, the most likely culprits are dinoflagellates, a form of microscopic phytoplankton, says Diana Varela, a professor of biology and earth and marine sciences at the University of Victoria.

A chemical reaction in the cell triggered by a mechanical force – such as moving your arms while swimming or pulling a paddle through the water – creates the glow, she said.

Varela said the purpose of bioluminescence was not entirely clear, but many believed it was a defense mechanism to deter predators.

“So they flash and that deters a predator from eating them,” she said. Another theory, which Varela thinks is a bit “far-fetched,” is that the light acts like a “burglar alarm” and attracts a second predator that feeds on a dinoflagellate predator.

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The single-celled dinoflagellates are too small to be seen with the naked eye, but when arranged in a chain or colony and triggered, they become visible as small flashes of light, she said.

Dinoflagellates are found in all the world’s oceans, but are more common in warmer waters, said biologist Patrick Walshe.

Warm temperatures in the summer lead to plankton blooms around Vancouver Island, which increases the concentration of dinoflagellates and increases the likelihood of seeing the glow, he said.

Walshe recommends finding a dark place with no light pollution. The best time is at least an hour after sunset on a new moon or before the moon has risen, he said. The light may be easier to see in shallow or sheltered water, but the organisms can be found virtually anywhere, he said.

“Even on the ferries you can see it at night. Look at the wake behind the ferry, it’s illuminated,” he said.

Using a diving mask or goggles is “even more spectacular” because it reduces reflected light, Walshe said.

“When snorkeling, you can see little fairy trails behind the fish.”

While Frederiksen has spent many magical nights on the water, twirling her paddle and drawing glittering lines in the water, one evening on a multi-person paddleboard with friends stands out for her.

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A curious seal came closer and swam under and around the board.

“You could see the glittering outline of the seal on our board,” said Frederiksen. “And that’s really great because seals usually disappear as soon as they go underwater. But that evening the opposite was the case because when the seal lifted its head up you could hardly see it, but you could see the body underwater, glittering.”

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