Beaked whale3/22/2023 The Center for Naval Analysis analysed complete data, including classified information, Adams said, determining there was “insufficient evidence to claim a relationship between sonar use and beaked whale strandings in the Mariana Islands”. The US Navy declined an interviewed but in an email, Pacific Fleet spokesperson Lieutenant James Adams said: “Whales strand for a wide variety of reasons, including due to natural causes”. “There’s still a need to answer some basic questions about beaked whale populations and behaviour before we can understand the impact of sonar-associated strandings.” Level ‘B’ Harassment “It does seem to be clear that beaked whales are more sensitive to navy sonar than other species,” Simonis said. “The number of animals that actually show up dead on the beaches may only be a fraction of the animals that are dying at sea,” said Simonis, saying that far fewer animals in pelagic waters are recovered compared to coastal species, no matter the cause of death. The team detected three beaked whale species and examined eight Cuvier’s beaked whale strandings, of which three were confirmed to have occurred within six days of sonar use in the area, similar to other beaked whale strandings in other parts the world after anti-submarine activity.Ī leading hypothesis suggested sonar may cause the whales to surface too quickly, forming bubbles in their blood or vital organs similar to decompression sickness, known as the bends. The lead author, acoustic ecologist Dr Anne Simonis, said the team recorded in waters between 6 meters off Saipan and Tinian islands at timed intervals for up to 12 months, analysing recordings of the whales’ distinctive echolocation clicks, which fall beyond the range of human hearing but are easily identified using a spectrogram to visually represent sounds. There are growing concerns US military activity – including sonar – off Guam and the Mariana Islands is contributing to whale strandings. The study reported eight stranding events between 2006-2019 involving at least 10 whales.Īn adult males Cuvier’s beaked whale stranded. In February, a team of researchers from the National Oceanic and Atmospheric Administration (NOAA) and Scripps Institution of Oceanography published a study examining how the navy’s use of mid-frequency active sonar may contribute to whale strandings in the Marianas. Initially, the military denied it was using sonar, only to later admit it had after divers presented video in which sonar could be heard. Tibbatts recalled a 2015 live stranding of a Cuvier’s beaked whale which later died. If it washes up dead – over 80% of the time, Tibbatts told the Guardian – or dies while stranded, Tibbatts performs a necropsy, taking tissue samples, measurements, and photos. If the animal can be saved, it’s pushed back into the water. When strandings occur, Tibbatts is the first called. The timing of the strandings, and their proximity to sonar, have led him to believe they are related. Since 1998, fisheries biologist with Guam’s department of agriculture, Brent Tibbatts, has documented 30 marine mammal strandings – 13 of them since 2010. In particular, Cuvier’s beaked whales, known for deep dives documented to last for hours, may be acutely vulnerable to sonar.Īble to dive to nearly 3,000 meters, Cuvier’s beaked whales can feed beyond the reach of competitors and predators, but not out of range of navy sonar. Map of the Mariana Islands Training and Testing Study Area Photograph: Mariana Islands Training and Testing
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