The Occurrence of Lymphocystis in Micropogon undulatus and Cynoscion arenarius from Mississippi Estuaries

Abstract

Lymphocystis was observed in Atlantic croakers (Micropogon undulatus) and sand seatrouts (Cynoscion arenarius) collected from brackish waters of the Mississippi Gulf Coast. This is the first report of lymphocystis in Fishes of the Gulf of Mexico and adds one family and two species to host records. Microscopic examination of the tumors revealed several histologic differences in the lesions of the two species. Mature tumor cells in the croakers were larger than those in the sand seatrout. In the croakers, these cells were closely packed and their hyaline capsules were usually confluent. In the sand seatrouts, the tumor cells were rarely confluent and were usually widely separated either bv interstitial connective tissue or by an amorphous, hyaline matrix that filled the intercellular. spaces. A preliminary description of the histology of the neoplasm was included. Ecological factors of the sampling stations where fishes infected with lymphocystis occurred were compared with stations where lymphocystis was not encountered. The pollution load was much greater in estuarine systems where lymphocystis was encountered. The chemical and physical differences observed at these stations were discussed.