Pilot Error

Of the 450 Long-finned pilot whales stranded on sandbanks in a Tasmanian harbour, only around 50 have been successfully coaxed (by volunteers) back out to sea (https://www.theguardian.com/environment/2020/sep/23/more-than-450-whales-now-stranded-in-tasmania-after-rescuers-discover-pod-of-200-dead). This is Australia's worst, recorded mass stranding of whales and probably reflects the difficulty these cetaceans have with shallow waters, that are in close proximity to deeper channels. Their sonar systems don't cope very well with such conditions.