Where did National Geographic explorers discover a glow-in-the-dark sea turtle?

During an expedition near the Solomon Islands in the South Pacific, National Geographic explorers David Gruber and Markus Reymann discovered a glowing sea turtle by accident — the two were there looking for sharks.

After spotting the first turtle, shown in the photo above and video below, Gruber and Reymann observed other turtles with the same trait, called biofluorescence, which is the ability to absorb blue light and emit green, red or orange light.

These biofluorescent sea turtles are considered critically endangered.