Unusual Eel

I caught this fellow last year while working in a stream in Waldo County, Maine. I'm nearly certain this isn't shocker burn - we saw him swimming well ahead of us, and he had already had this color pattern. The eel appeared to be quite healthy, although I did anesthetize him for the picture. Any ideas on what might cause this anomaly?

The eel appeared to be quite healthy, although I did anesthetize him for the picture.

Does 'anesthetize' mean that you knocked it out? Or killed it?

I mainly just wanted to ask that question; I don't really have much helpful advice about your eel. But I do remember reading somewhere that eels were ridiculously long-lived. They start their lives in the ocean as floating eggs, then slowly work their way back up the rivers into fresh water over decades of time. The article said that eels could easily live to be the same age as people, and that they transitioned from one form to another (larval, juvenile, etc) as they did so. So my guess is that this is an eel transitioning from larva to adult. But, you know, it's just a guess. I don't know anything about eels.

Anesthetize as in temporarily knocked out, as opposed to euthanasia.

Eels do have a leptocephalus stage prior to entering streams, but those are much, much smaller. The leptocephalus change into glass eels, then into juveniles and finally adults. My understanding is that adults turn a silver color as they head back out to sea. For Anguilla rostrata, I've heard that freshwater residence may last anywhere from 7-25 years.

He's piebald! That is really neat. No real insight from me, but I would guess it is likely to be a mutation, similar to those in captive animals with similar pigment anomalies. Injuries and infections can also cause weird patterns, but they're usually less regular than this.

He's piebald! That is really neat. No real insight from me, but I would guess it is likely to be a mutation, similar to those in captive animals with similar pigment anomalies. Injuries and infections can also cause weird patterns, but they're usually less regular than this.

Its possible that its a genetic mutation. This stream is a tributary to the Penobscot river, which is known to have lots of nasty chemicals in its benthic sediments. And of course, genetic mutations can happen in the absence of mutagenic chemicals. I saw a piebald robin a few years back, but its pattern was very irregular. I've handled 10,000s of eels, and this fellow was in a class of his own.

Holy Crap! You could make a mint if you could breed those for striper fishermen.