TWENTY-FIFTH ANNUAL EASTERN FISH HEALTH WORKSHOP MARCH 10-13, 2000   Leukocyte Function: Investigations On Fish Health In Selected Tributaries Of The Chesapeake Bay       Chris Ottinger1, Christine Densmore1, Vicki Blazer1, Craig Harms2, Deborah Cartwright3, Suzanne Kennedy-Stoskopf2, Larry Pieper4, Paul Peach1   1National Fish Health Research Laboratory, Leetown Science Center, Biologic Resources Division, USGS, Kearneysvile WV 25430. 2College of Veterinary Medicine, North Carolina State University, Raleigh NC 27606. 3Johnson Controls World Services, Inc., National Fish Health Research Laboratory, Kearneysville WV 25430. 4Maryland Department of Natural Resources, Stevensville MD 21666                 Reports of high incidences of fish with skin lesions in the summer and fall of 1996 and 1997 in the Pocomoke River and other tributaries of the Chesapeake Bay stimulated a great deal of public and scientific interest.  These skin lesions range from small pinpoint hemorrhages to abrasions to deep ulcers.  In addition, there were two fish kills involving primarily Atlantic menhaden (Brevoortia tyrannus) in the Pocomoke River in August 1997.  Preliminary findings suggest that some factor or group of factors is leading to epidermal damage and/or immunosuppression allowing for a variety of organisms to cause disease in various fish species. One objective of this study is to evaluate the overall health of white perch (Morone americana) in these tributaries using necropsy-based, physiological, histological and immunological techniques. White perch from five tributaries were collected in June, August, and October of 1998 and 1999. Results for macrophage and lymphocyte functional assays and transforming growth factor-? expression analysis indicate both significant differences between tributaries and significant changes over time. Macrophage aggregate studies are in progress and will also be presented.   Return to 25th Annual Eastern Fish Health Workshop Return to Leetown Science Center Home Page