Journal of Zoo and Wild/1ft' .\It'dicint' 286-292. 1995 Copyright 1995 by American Association of Zoo Veterinarians CHRONIC REFRACTORY EMESIS ASSOCIATED WIT A COLONIC LESION IN A CALIFORNIA SEA 10 (ZALOPHUS CALIFORNIANUS) \VilIiam G. Van Bonn, D.V.M, Sam H. RJdgway, D.V.M, Ph.D., and Bruce H. Williams, D.V.M. Abstract: An adult castrated male California sea lion, Zalophus ealifornianus. developed a pattern of intermittent vomiting of fish that progressed and was unresponsive to medical and behavioral intervention. The animal had been collected from the wild in 1985 and was utilil.ed in the U.S. Navy's marine mammal program until March 1993. ecropsy findings included a ruptured saccuJar diverticulum of the distal colon and a peritoneal effusion. Campylobaeter spulorum. Clostridium perjringens, Escherichia coli , and Streptococcus canis were isolated from the peritoneal effusion. Large numbers of gram· positive bacilli, consistent with Clostridium spp., were observed within the affected tissues on histologic sections. The cause of the gross lesion in the affected section of gut was not evident. A long·standing ulcerative or possibly obstructive lesion responsible for local stasis and conditions favorable for clostridial overgrowth was suspected. Gastrointestinal clostridial in· fections have not been previously reported in a California sea lion. Additionally, there bave been no reports of vomiting associated with large colonic disease in marine mammals. Key words: Sea lion Zalophus californianus. Clostridium spp. vomiting colon enteritis. CASE REPORT An adult male castrated California sea lion, Zalophus californian us. developed a pattern of intermittent vomiting offish that progressed and was unresponsive to medi- cal and behavioral intervention. The animal had been collected from the wild in 1985 and was utilized in the U.S. avy's marine mammal program until March of 1993. Prior to the development of the vomiting activity the animal had no significant med- ical problems. Medical intervention was limited to routine bilateral orchectomy in 1987, semi-annual comprehensive physical examinations, and pre-transport health as- sessments. The animal was maintained on a diet of three species of fish (Thaleichthys pacificus, Scomber japonicus. and C/upea From the Naval Command, Control and Ocean Surveillance Center, Research Development Test and Evaluation Division, Code 5107, 49620 Beluga Road, Room 200, San Diego, California 92152-6330, USA (Van Bonn, Ridgway); and the Armed Forces Institute of Pathology, Building 54, Room G-117 , Washington, D.C. 20306-6000, USA (Williams). Address reprint requests to Dr. Van Bonn at CCOSC RDTE DIV 511 , 53405 Front Street, Room 200, San Diego, Cal· ifornia 92152·6530, USA. harengus pal/asl) and squid Loligo sp. Ad- ditionally, the sea lion received two tablets of a vitamin /mineral supplement (Sea Tabs ® Pacific Research Laboratories, Inc., 1951 Willow Glen Drive, El Cajon, Cali- fornia 92019, USA) and 800 IU vitamin E daily in the first fish fed. In June 1992 concern developed over weight loss and reports offrequent vomiting when the animal returned to the water after a feeding session. The trainers described vigorous forceful abdominal contractions with extension of the head and neck. This activity was observed immediately after feeding and at several occasions throughout the training day. Results of physical ex- amination, hematology, serum biochemical analyses, and serial fecal flotations were within normal limits for the species and within the range of values obtained from this individual during the five previous years. Feeding of the total ration was spread out over a 6-7 -hr period and the animal gained weight and the vomiting episodes became infrequent. In February 1993 handlers again reported frequent vomiting after feeding. The animal was clinically normal between episodes and was performing learned behaviors exccp-