Temporal Variation In Immunologic Biomarkers:  Are Single Snapshot Studies Of Any Value     Chris Ottinger1, Vicki Blazer1, Christine Densmore1, Deborah Cartwright2, Luke Iwanowicz2, Sandra Page1, and Larry Pieper3     1National Fish Health Research Laboratory, Leetown Science Center, Biologic Resources Division, USGS, Kearneysvile, WV 25430; 2Johnson Controls World Services, Inc., National Fish Health Research Laboratory, Kearneysville, WV 25430; 3Maryland Department of Natural Resources, Stevensville MD 21666        In recent years there has been interest in using immunologic biomarkers as indicators of environmental disturbance. A number of functional assays such as macrophage phagocytosis, bactericidal activity and superoxide anion production, as well as a number of lymphocyte assays have been used in field studies. Differences have been noted in some studies between contaminated and reference sites. However, there has been little research directed toward understanding seasonal effects and how factors other than contaminants may influence these functions and hence the results obtained when comparing sites. Ongoing fish health studies in Chesapeake Bay tributaries offered an opportunity to compare functional assay results both spatially and temporally. White perch were collected in June, August and October of 1998, 1999 and 2000 and additionally in April and December of 2000 and February 2001. Significant differences were noted in functional assays among the tributaries but also within individual tributaries among the sample periods. Potential impact of seasonal factors and other influences will be discussed.