TWENTY-FOURTH ANNUAL EASTERN FISH HEALTH WORKSHOP Royal Pavilion Resort, Atlantic Beach, NC MARCH 9-11, 1999 The Effect Of Fish Density On The Survival Of Rainbow Trout Fry During An Infectious Pancreatic Necrosis (IPN) Epidemic Julie Bebak1, Philip E. McAllister2, Ray Boston3, and Gary Smith3 1Freshwater Institute, P.O. Box 1889, Shepherdstown, WV 25443 USA; 2U.S. Geological Survey/BRD, National Fish Health Research Laboratory, 1700 Leetown Rd., Kearneysville, WV 25430 USA; 3382 West Street Rd., New Bolton Center, University of Pennsylvania School of Veterinary Medicine, Kennett Square, PA 19348 USA One consequence of the intensive culture of animals is an increased risk for outbreaks of infectious disease. Few studies have characterized or quantified this problem as it relates to the intensive culture of finfish. In two separate controlled, replicated experiments, susceptible rainbow trout fry were exposed to infectious pancreatic necrosis virus via the introduction of fish infected with the virus. One, two or three infectious fish were introduced to tanks containing varying densities of susceptible fish. The mortality data was subjected to survival analysis, which epidemiologists often use to investigate "time to an event" problems affecting human and animal health. For susceptible fish, the probability of survival to the end of the experiment was related to fish density and the number of infectious fish that were added. For example, when one infectious fish was added to the tanks, the probability of surviving to the end of the experiment was greater for fish from the lower density tanks. However, when three infectious fish were added, the probability of survival was similar for all tanks. Characterization of the relationship between fish density and infectious disease epidemics will facilitate the development of management strategies that optimize fish density in intensive aquaculture systems. Return to 24th Annual Eastern Fish Health Workshop Return to Leetown Science Center Home Page