Lake whitefish (LWF; Coregonus clupeaformis; Family Salmonidae) are economically and ecologically important indigenous Great Lakes (GL) fish. However, recent declines in GL-LWF abundance, growth, and early life stage recruitment have generated substantial concern. Although numerous studies have attempted to determine what may be driving these recruitment declines, the potential role(s) of infectious diseases, particularly those that can be vertically transmitted in other fishes, has not been thoroughly investigated. To this end, five sites within Lakes Superior, Michigan, and Huron were selected based upon good (n=3) and poor (n=2) LWF recruitment histories, after which spawning-phase LWF were collected over two years (n=60/site/year). Gross pathological examinations were performed and tissues collected for hematology, bacteriology, and virology. Although analyses are ongoing, several important findings have been thus far made. For the first time, Flavobacterium psychrophilum, causative agent of bacterial coldwater disease, was detected in systemically-infected GL-LWF, a matter of significance given the bacterium’s ability to be vertically transmitted and cause substantial early life stage mortality in other salmonid species. Likewise, Renibacterium salmoninarum, etiological agent of bacterial kidney disease, and Carnobacterium maltaromaticum, cause of pseudokidney disease, were detected in the gonads and reproductive fluids of spawning phase GL-LWF collected from multiple sites, thereby highlighting a potential pathway by which resultant offspring could become infected. In this context, juvenile GL-LWF (n= 325) were collected from beaches adjacent to previously sampled broodstock locations for microbiological and pathological analyses, which are underway. In the final study phase, laboratory experiments will assess, for the first time, the effects that R. salmoninarum, F. psychrophilum, and C. maltaromaticum have on juvenile GL-LWF health. Although findings to date have generated more questions than answers, the discovery of multiple systemic infections in spawning-phase GL-LWF, including within their reproductive tissues, highlights the possibility for transgenerational pathogen transmission and subsequent potential negative health effects in the resultant offspring.