Most of the bioluminescence produced at this level of the ocean is blue. Some predators, however, are able to produce red light. Which is more of an advantage, why?

The red light is more advantageous.

Explanation:

Predators that are producing red light have advantage because they can see their prey but their prey can't see them, since most of them see blue light.

Some also light up their red light to attract mates.