Hyperpigmented Melanosis

[Dead River]

I've caught a lot of bass (largemouth) with hyperpigmented melanosis over the years. but this has to be hands down the worst one I've ever seen. I read that Auburn University was researching the cause of this, thus far it's unknown. Anyone know anything?

 

The head of this fish reminds me of a dark skinned person that has those white splotches from a pigmentation issue - the bass looks a fleshy pink color as if it's albino.

 

[basshole8190]

That bass looks like it has a death mask on! Super cool. never caught one with the pigment issues on its face. the few I've caught have it on the tail or around the latteral line.

[ww2farmer]

It's fairly common around here. Some days I will catch multiple fish with the blotches. AFIAK no one knows what causes it, or what it means, but it is generally said that fish with these markings come from very healthy bodies of water.

[0119]

Bass shows and mags are making a big deal to say its nothing lately.  Never in over 50 years of bass fishing had I seen it, heard of it or caught a fish with it.  I've been buying tons of old bass magazines from ebay and prefer reading them to newer stuff.  I've never found a mention of it in any bass periodical from the 70's or 80's.  In the last 3 years it now seems to be on every bass I catch.  I think its indicative of our declining water quality.

[The Rooster]

Absolutely 0119. I think anytime the people in charge don't want the common people to worry about something strange happening they will go public with all kinds of messages downplaying whatever it is that's happening. Clearly this is not normal, and also clearly it is a result of poor water and environmental conditions. That cannot be healthy for the fish but as long as it's still able to swim and eat it will still continue to act like a fish and we'll start to see numbers of these fish caught. As far as we know, that's a cancer on those fish. In time they will go belly up. Remember, the definition of cancer is abnormal cell growth. I believe I can say with confidence that those fish have cancer. It would make me question how much contact I even want to have with the water they're in.

[Mainebass1984]

 I have spoken about this with the fish health biologist for the state of Vermont and the bass biologist for the state of Maine. It is very, very rare in Maine. In Vermont though it is common in Lake Champlain and in the Conn river below the nuclear power plant. Basically it is skin cancer in bass that causes all the chromataphores to produce extra melanin which causes the black pigmentation. They know that there is something disrupting how the chromataphores receive information to determine how much melanin to produce which gives fish there color. They have not been able to identify what is causing the disruption.

[Team9nine]

I've caught a lot of bass (largemouth) with hyperpigmented melanosis over the years. but this has to be hands down the worst one I've ever seen. I read that Auburn University was researching the cause of this, thus far it's unknown. Anyone know anything?

 

 

 

The Auburn group never came up with a definitive conclusion. A new group has now taken up the research, so we'll see if they can come up with anything. To the best of my knowledge, and from all the biologists and researchers I've spoken with, there is still no published studies stating a specific cause, so any conclusions drawn at this point would need to be taken as speculation. Some waters it is very prevalent in, and some waters it is almost non-existent, even within the same area of a given state. I've got pictures of bass I've caught going back to the late 80s showing these marks, so it has been around for quite a while. One would also need to come up with an explanation of why this appears to be almost completely relegated to the LMB/SMB. In some of the waters I fish where it is very prevalent, I have never caught a white bass, crappie, bluegill, or catfish that had these markings to the best of my recollection. Seems very odd that if it was a water born pollution-based cause that it would only affect a single species to this degree.

 

-T9

[Avalonjohn44]

I've read a few articles about it over the last few years, but no theories have ended up being widely supported yet. A popular theory is that the bass had some sort of trauma to the pigmented area, most likely blunt force, as any other injury would leave an easily identifiable scar. There was one big bass with black patches living for several years in the BPS Orlando aquarium, so whatever it is, doesn't seem to be immediately detrimental to the bass.

[Avalonjohn44]

Interesting article: http://www.another site.org/bassfish/articles/T205.htm