Vibrio bioluminescence Vibrio fischeri inhabits the open sea(in small densities), as well as in squid light organs(in high densities) Luminescence occurs only at high cell concentrationsVibrio bioluminescence • Vibrio fischeri inhabits the open sea (in small densities), as well as in squid light organs (in high densities) • Luminescence occurs only at high cell concentrations