Our good friend Adam Guy, all the way from the waters of Japan, sent me these amazing photos. We’ve talked about this tongue eating fish parasite before, but these may be some of the best photos to date that I have seen of this particular parasite. Good job Adam!
On Sunday fishing near Yokosuka I caught a fine example of Japanese horse mackerel (Trachurus japonicus) and when I was preparing the fish that evening, it turned out to be harboring a parasite known here in Japan as ‘uonoe’ (Rhexanella verrucosa). Apparently these creatures affix themselves to the tongue and help themselves to whatever the host fish eats. As you can see in the photos I have attached, with their multiple legs like hooks, they seem well adapted to their niche; I had to behead the mackerel to remove the parasite from its tongue. According to the literature here, these parasites are common in red sea bream and yellowtail amberjack (kingfish), but the two examples I have come across personally have both been in horse mackerel. In both cases, the fish appeared outwardly healthy and did not seem emaciated or unwell at all. The parasitic infection did not appear to affect their flesh either, as they were quite delicious.
All the best,