TWENTY-THIRD ANNUAL EASTERN FISH HEALTH WORKSHOP JOHN CARVER INN, PLYMOUTH, MA 30 MARCH - 2 APRIL, 1998 Diseases Of The Toadfish, Opsanus tau Roxanna Smolowitz Laboratory for Aquatic Animal Medicine and Pathology, University of Pennsylvania, Marine Biological Laboratory, Woods Hole, MA The toadfish is an important laboratory animal at the Marine Biological Laboratory (MBL) and many other institutions. It is used in the study of diabetes, muscle physiology, behavior and communication and neurophysiology. During the summer toadfish can be found in inshore areas with rocky bottoms. In the winter they migrate to deep waters, bury themselves, and remain in a torpid condition until the spring. The MBL collects toadfish during the summer and maintains them over the winter at the Marine Resources Center to provide research specimens year round. Over the past few years several diseases have occurred in the toadfish that were maintained at the MBL. Bacterial pericarditis caused by Edwardsiella sp. produces severe flocculent pericarditis, acities and multifocal, large (up to 5 cm diameter), liquefactive granulomas in various organs. Flexibacter sp. dermatitis caused focally extensive ulcerative dermatitis and cellulitis with loss of portions of the ventral abdominal wall in some animals. Stephanostomum sp. (digenetic trematode) infection of the pericardium can result in severe restrictive pericarditis with mild acities and peritoneal adhesions. Pseudomonas sp. caused chronic low level morbidity and mortality characterized by multifocal small caseous to liquefactive granulomas primarily in abdominal organs. Argulus sp. (lice) infestation of the dermis is suggested as the initiating cause of bubble disease from which Brevundimonas vesicularis has been isolated. While Argulus and Stephanostomum have been identified in wild fish, the occurrence of the other diseases and the morbidity and mortality that result from all of these diseases, have not been reported in feral fish. Whether they exist in the wild or only occur when the fish are housed and maintained in an aquaculture setting is unknown. The previously undescribed spectrum of diseases occurring in wild caught Opsanus tau held in long term confinement at the MBL represents another example of what happens when a wild species undergoes culture attempts.   Return to 23rd Annual Eastern Fish Health Workshop Return to Leetown Science Center Home Page