Looking like giant leaves floating in the sea, thousands of Golden Rays are seen here gathering off the coast of Mexico.
The spectacular scene was captured as the magnificent creatures made one of their biannual mass migrations to more agreeable waters.
Gliding silently beneath the waves, they turned vast areas of blue water to gold off the northern tip of the Yucatan Peninsula .
Sandra Critelli, photographer, stumbled across the phenomena while looking for whale sharks.
She said: 'It was an unreal image, very difficult to describe. The surface of the water was covered by warm and different shades of gold and looked like a bed of autumn leaves gently moved by the wind.
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Sandra Critelli's website: www.sandracritelli.com