What Are These Spots on the Bass?

Type: Nontidal
Region: Central
Location: Patapsco State Park

I was recently fishing the pond in Patapsco State Park. I have caught 2 largemouths with spots like this, but see them on other bass a lot. This is the worst I've seen though. Any idea what I should do with one next time I catch one with it?

DNR Response: It appears that there are raised masses over the reddened area, along with some missing scales. This type of lesion could be bacterial, but more likely parasitic. Parasites tend to form encysted structures in the flesh of fish. We can�t identify it based on an image and there are too many types of parasites to list. If it is a parasite, they go through natural stages that involve fish as a host for part of their life cycle. In some cases, there is little effect on the fish and in others, fish may be severely diseased. Fish released in this condition may recover and heal fully.

We recommend that fish with lesions be discarded and not consumed. Parasites that infect fish are generally not infectious to humans but many bacteria are. Even if this lesion was caused initially by a parasite, it may also carry bacteria. We also recommend that you try to avoid direct contact with these types of lesions when you handle diseased fish and wash your hands. Waterless hand sanitizers are effective and convenient.