2003  -  We were fishing in PML this fall and pulled up several 22-inch trout that had lesions on them. Each one had a little parasite like the one below. The local Fish and Game gal said to just scrape them off and eat the trout - we decided against that. We released the trout, but now I wonder if we should have kept them out of the water to help contain the pest. The whole thing was a milky white color and a bit translucent - the two appendages look darker in this photo than they really are.

February 2004:

A high school teacher gave me one lead...

Looks like a copepod crustacean called Ergasilus.

However, references mention that it is found on the fishes' gills.  Like yours, mine were found all over the fish.  There are probably lots of different species.

Eric Boyce

This was a good lead and I responded: 

Hi Eric,

You may have seen this picture:  http://www.dnr.state.md.us/fisheries/recreational/articles/sealice.html  of Sea Bass and this one http://www.coloradokoi.com/koip.htm of Koi. 

Those certainly look the the buggers we found. Interesting that these sites also say they are harmless to humans; still . . .  ugh!

Jim

A park ranger from New Mexico sent this nice email to me:

Sir, 

I believe that the parasite on your trout is an anchor worm. I'm a Boating Officer in NM for the State Parks department, and we have had trout with anchor worm, and they look just like the photo on your website. I have been told by the Game and Fish biologist that they are only superficial, and safe to eat if they are tweezed off. I don't see myself doing that, but that's what I have been told. You can run a google search for "anchor worm in trout" or just anchor worm, and you will get many hits. I hope this information helps you. I am sending you a site for the parasite to check out. If you are ever in New Mexico, please stop by one of our many great State Parks and do some fishing. We have more than just deserts out here!

-Aubony Burns
MEO/Park Ranger

His link was to The Ohio State University site of parasites, which is now off line.

August 2007: Anchor worm

A google search on anchor worm brought up this page from Purdue. At the very bottom of the page they call it "a typical Lernae sp. anchor worm". I think this is the closest match I've seen.