A device and method of use for measurement of in-situ bioluminescence generally comprising an acoustical pulse generator, a detector chamber, a lens assembly and a photomultiplier tube. The generator comprises transducers which can generate acoustical energy in the object field of the device. The acoustical energy provides a stimulus of aquatic organisms within the object field (typically an aqueous volume) to produce the bioluminescence. The generator is positioned outside of the detector chamber and the photomultiplier tube and lens assembly are mounted within the chamber. The lens assembly restricts light to the photomultiplier tube of that bioluminescence light originating only from the volume. The photomultiplier tube detects the bioluminescence generated by any aquatic organisms in a captured volume or if a changing measurement occurs by water flow in the volume. The output of the photomultiplier tube is provided to a controller to be analyzed.