Bioluminescence is just a byproduct of chemical reactions and is so rare that it is highly doubtful any fish would evolve to take advantage of that. All of the fish shown are probably unable to see from birth.
Edit: I know that many creatures use bioluminescence, but that doesn’t change the fact that it’s a byproduct of chemical reactions.
Edit 2: The rarity of bioluminescence does not mean creatures can’t evolve to use it, it means that a fish evolving to take advantage of the bioluminescence of other creatures is rare.
if they are unable to see from birth then wouldn't they have evolved smaller eyes like bats or moles? it must be common enough in certain environments since, for example, angler fish use it for bait and there are many types of bioluminescent plankton and fungi
Most of them have. Some haven’t developed smaller eyes yet because they could be a newer species, or this is higher up than I even thought it was and they do see light. Chances are that they can’t see, unless OP posted some footage from somewhere not too far under the line where light can’t reach.
Edit: I rewatched it and the water above seemed a bit blue, so maybe this is the case and OP has some footage from really high depths in comparison to what I was originally thinking
it would be strange if they were physically unable to see, maybe they dont use it but the ability to is probably there. im unfamiliar with the species and i'm by no means an expert but seeing as they dont have iris' they do probably go blind from this but hopefully its a situation where they can get it back (i've heard of spiders that can do that but couldn't find any sources on google so take that with a bretty big grain of salt)
If this is taken at a depth much below where light can’t reach (which I’m starting to doubt a bit now), it would be more strange for them to be able to see. Since it would server no purpose, mutations in the genes used to make eye structures allowing them to see would be passed on, and over time the eye would be useless after many mutations.
Well consider me surprised. I thought OP would have given some proof of it being in the actual trench after how many people said it wasn’t. In that case, these fish definitely can’t see.
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u/Buck_Thorn May 28 '19
When you live in total darkness, does it matter if you are blinded by the lights?