Mitigating the contingent effects of anthropogenic noise frequently relies on the continuous surveillance of the acoustic source’s environs. Recent advances in ship-based perimeter surveillance, using a state-of-theart 360° IR-scanner to generate a thermographic video stream, now allow automatic real-time detection of whales, facilitating effective observations both night and day. So far, tests proved the system’s reliable performance at ranges up to ca. 5 km in polar, sub-polar and temperate environments (waters cooler than 16°C), under low visibility (particularly night-time), and at high sea states (corresponding to Beaufort 7). Additional recent studies in subtropical waters confirm for waters up to 22°C the discriminability of whale blows at somewhat reduced, yet still sufficient, ranges. The system’s current implementation provides automatic detection, localisation, documentation and real-time verification, serving as assistant to the marine mammal observers who are thereby relieved from the bulk of their protocolling duties. Noteworthy features are the system’s unwavering alertness 24/7, its quasi-360° coverage, and its highest possible thermal sensitivity (and hence long detection ranges) due to a cryogenically cooled sensor head.