Melanistic Trout?

[PSUFishMenace]

Hey guys, do any of you know if there is such a thing as a melanistic trout? Caught a brown trout today that was super dark, and was just wondering if it's a genetic mutation or a result of living in the shade most of its life. I have heard of black rainbows but not browns. Will post pics later.

TIA

 

[jayL]

Most of the very dark trout that I've seen were either fresh off the redd, or near death.

That's my experience with it. I wouldn't doubt that they can run darker under other circumstances, though.

 

[streamerguy]

I've noticed it with steelhead, but thats because they're spawning obviously. This one brookie stream I fished All of the fish were much darker than the fish I caught in other streams. I would think it has to do with shade, but all the streams I've fished are well shaded. Water chemistry maybe?

Here's a picture of one of the brooks.

 

[PSUFishMenace]

I've caught a few brooks like that, usually way up in headwaters.

I'm leaning toward the brown I caught just being adapted to the shade or dark stream bottom but I'd still like to hear what you all think about the possibility of it being a genetic mutation.

 

[wildtrout2]

I've caught a few very dark wild trout, both brookies and browns, and they were always in heavily shaded spots on the stream. Here's one of them. I think this was actually an old fish.

 

[JackM]

You could probably account for it either way and wouldn't know which is correct without further investigation. There is variety in the survivors of a brood and also some pigmentation changes that can be attributed to habitat and diet.

 

[salmonoid]

wildtrout2 wrote:
I've caught a few very dark wild trout, both brookies and browns, and they were always in heavily shaded spots on the stream. Here's one of them. I think this was actually an old fish.

Agreed - your fish immediately reminded me of an OLD fish I caught last year that was almost black. There are so many variables that go into color - habitat, sunlight, diet, genetics, spawn, etc.

 

[PSUFishMenace]

Here are the pics, first two are of the one I caught today, last is a more typical coloration for this stream.

I would not have thought much of this fish if it was a small mountain headwater with lots of boulders and shade, but the stream is a limestone spring creek which is why I found it odd. It stuck out like a sore thumb in the water but was just cruising the bank like it had nothing to worry about. That said, I did see another very dark trout feeding near an undercut bank (couldn't catch that one), so I think the color is probably related to the habitat in this case.

 

[Chaz]

The brookies are called hemlock trout because they live in the shade of hemlocks all their lives. They are much darker and more colorful because the contrast is greater. I've also caught very dark browns in well shaded places, one in particular was in Cumming Hill Creek below ahigh waterfall in deep shade under hemlocks. It was black and I believe I have a photo of it somewhere, if I can find it I'll post it.

 

[gfen]

while i'm sure melanistic trout exist, i think you've just gone and caught one with a tan. i would think something that met truly melanistic morph qualities would be much blacker than that, and there's still definate golden and red tones in him.

 

[Mike]

When I read your post I expected to see a truly dark brown trout in the photos. While darkened, the color of your fish is common. Dark browns are very dark, owing usually to one of two things.......1)matching their color to a dark environment, such as the color often seen when a brown is suddenly pulled from under a root wad, jack dam, or undercut bank 2) matching their color to a perceived dark environment. In that case, blindness will lead browns to be completely dark and in cases where they are blind in only one eye, that side of the fish will be dark. Your upper photo seems to show that the fish may have a cataract, which could lead to a darkened tone.

 

[SBecker]

Mike wrote:
blindness will lead browns to be completely dark and in cases where they are blind in only one eye, that side of the fish will be dark. Your upper photo seems to show that the fish may have a cataract, which could lead to a darkened tone.

That is pretty interesting.

 

[PSUFishMenace]

Thanks for your comment Mike, I never knew that blindness would do that. An eye problem could explain why this fish was hanging out in the open...he probably thought he was in the shade! Could also explain why it took me so many casts to get him to take!

 

[JeffK]

The dark color isn't odd, but it is the wrong spot. Maybe the fish was moved from it's prefered spot by the flood?

In one stream I fish there are dark and light bottoms and dark and light fish develop. If the fish doesn't match the bottom it usually stands out like a sore thumb and is usually not on the feed. I attribute that to the fish being displaced from its normal lie for some reason.

 

[pcray1231]

Displaced,

Or, as Mike said, blindness or vision problems, thus preventing the fish from adjusting its color to the background.

Thanks for the comment, Mike. I kind of knew/observed that fish change their color like that, but wasn't sure if it was diet, sunlight, etc. I've also seen a half and half fish before, and it confused me how they got that way (seems to rule out diet). Had never tied it to vision before. But I get the strong impression your comment is based on experience, and it makes complete sense, and I trust it.

 

[PSUFishMenace]

Jeff, I wondered that too, but the fish has been in the same area for weeks now (I actually thought it was a rainbow until I got a better look yesterday), not to mention it didn't really flood on this stream. Mike's explanation sounds best to me.

 

[PACOFRANSICO]

Ive caught a couple of browns outta spring creek down from the paradise that were almost black. But thats back last jan. I dont know if they darkin up like brookies?

 

[Maurice]

um, ah that one on the bottom IS a brookie. PACO.

 

[Eccles]

This subject has been pretty well studied, at least for teleost fish more generally - trout appear every now and then in the studies. The hormones (melanin concentrating hormones for eg) and biosynthetic pathways resulting in colour change are fairly well known as are the main cellular targets - chromatophores.
More interesting to us fisherman is that changes in colour result, as Mike indicates, to the perception of background colour or more accurately the integration of the intensity of light from above and below. But colour is also affected by the intensity of UV radiation (alteration in skin colour protect from harmful UV intensities), nutrition, health and social interactions and interspecific communication. The increase in intensity and boldness of colour patterns at spawning as well as the change during smolting all result from the same underlying process. Just the cues for intiating colour changes will be different.

Hmm, sorry, went a bit geeky there. But it is a fascinating subject.

 

[JackM]

Really, interspecific communication, too?