For some time, scientists have been investigating the possible reasons why some areas have higher incidents of turtles afflicted with fibropapillomatosis than others. It is becoming more and more evident that hgher incidents occur in areas with higher pollution — especially nitrogen runoff. For an easy read, and an introduction and summary, see John Virata’s article “Scientists Directly Link Agricultural /Urban Runoff to Firbropapillomatosis in Sea Turtles.” For a more research based approach, there are numerous academic (peer reviewed) journals that touch on this subject. I’ve included a few for your perusal.
Land use, Macroalgae, and a Tumor-Forming Disease in Marine Turtles
Eutrophication and the dietary promotion of sea turtle tumors