Keith Lockwood, Fisheries Biologist
- Oxford, MD
- Total Reports: 38
- View all reports by Keith Lockwood →
Posted on December 7, 2012 | Permalink
Location: Lower Patuxent River
Recently I received an inquiry about lumps or cysts in the intestines of a large white perch caught in the lower Patuxent River from a fisherman. I showed the picture to our fish health expert here at the Cooperative Oxford Laboratory Mark Matsche. Mark offered an explanation and our conversation drifted to other parasites seen in the gut cavities of striped bass and white perch from time to time in the Chesapeake Bay and its tributaries. The parasites that live in the intestines of fish and often form bumps or masses on the surface of the intestine are spiny headed worms. We see the species Pomphorhynchus bulbocolli in striped bass and other fish regularly. The worms that live freely in the abdominal cavities of fish are nematodes or roundworms. One species we have identified is Philometra rubra (in picture). There are likely other species, especially in other fish species.
The picture labeled spiny heads 1 shows numerous, large masses that form along the intestine in heavy infections. The photo labeled spiny heads 2 shows a section of that intestine opened up so that the body of the worm (yellow) can be seen inside intestine. The picture labeled nematodes shows a large group of roundworms in a striped bass. Although these fish parasites can be disturbing to the uniformed angler they do not present any danger to fishermen. All fish are hosts to a number of parasites from time to time; some are internal and others can be seen on the external surfaces of fish.