VETERINARY SERVICES AND SMALL-SCALE TILAPIA FARMS  

This presentation will report on tilapia disease cases on fish farms, primarily in Wisconsin, that have been assisted by the Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP).  In Wisconsin the DATCP is responsible for health requirements of imported fish, farm-raised fish, and all fish stocked into waters of the state.  Wisconsin has an abundance of trained private practice veterinarians who are available to fish farmers for VHS sampling and other disease work including observational surveillance. The DATCP works with private practice veterinarians to investigate fish diseases on fish farms.  All fish being stocked into waters are required to have a fish health certificate prior to stocking.  As a result of the elevated level of veterinary involvement with fish health in Wisconsin fish farmers can more readily pursue diagnostic and treatment assistance from veterinarians when disease occurs on their fish farm.  

One case involves whirling tilapia raised in indoor greenhouse aquaponic systems in Wisconsin.  The tilapia are raised in tanks that re-circulate water that flows to supply nutrients to various varieties of lettuce and herbs that are suspended on the surface of separate tanks.  The farms import young fry from another state and raises them to 1 pound market size.  The farm noticed whirling swimming behavior in fish that are near market size with mortalities in less than 3% of the population. A list of differential diagnoses included Streptococcosis, Epitheliocystis, Tilapia Iridovirus or numerous nutritional or water quality diseases.