Blue water at Westshore in Napier
Video by Codee Mavis Daley-Wilkins
Blue moon? How about blue ocean?
Hawke's Bay residents and curious passers-by were treated to a natural light show over the weekend when the ocean off Westshore Beach in Napier glowed blue.
Photographer Sajith Muraleedharan had heard about the phenomenon called bioluminescence and decided to chance his armon Sunday night to see what all the fuss was about.
He arrived at Westshore Beach around 7.30pm and over the course of two hours, he captured the ocean lighting up fluorescent blue.
"I've never seen anything like it. It's a once-in-a-lifetime opportunity for some people," he told the Herald.
"When it splashed on people you could still see it light up. It was incredible."
For more than two hours the Westshore Beach in Napier was glowing blue. A number of people even decided to take a swim. Photo / Sajith Muraleedharan
So what causes the glowing?
Bioluminescence occurs through a chemical reaction that produces light energy within an organism's body, which in many cases would be plankton in the ocean.
Not all plankton glow and those that do only glow sometimes.
They usually produce a blue or green light that glows stronger through movement in the waves or if people swim in the water.
Calm and warm sea conditions are usually needed as well, for the phenomenon to occur.
Muraleedharan told the Herald he's only ever seen photos of a bioluminescence and never imagined he'd see one in New Zealand.
"I've seen photos from the Maldives and different islands capturing this, but I was never expecting to witness this in New Zealand with my own eyes. It was amazing."
Bioluminescence is most common on a warm night after days of heavy rain, and conditions in Hawke's Bay, which has been hit by consistent rain over recent weeks, were perfect for it on Sunday.
Other witnesses to the blue light commented to Hawke's Bay Today that it was "such a stunning still warm night to sit on the beach and watch this amazing, rare phenomenon''.
