The Short Version
A peer-reviewed study did detect trace amounts of cocaine and caffeine in shark blood near Eleuthera, Bahamas — but the claim significantly overstates the findings. Cocaine was found in only 1 of 85 sharks, at nanogram-level concentrations far below any biologically meaningful threshold. Caffeine was more widespread (~24 of 85 sharks). The claim's assertion that these substances were "absorbed from contaminated ocean water" reflects a plausible hypothesis, not a confirmed pathway. The plural framing and "tested positive" language create a misleading impression of widespread drug contamination.