Jennifer Tennessen
September 10, 2024
Thanks to humans, Salish Sea waters are too noisy for resident orcas to hunt successfully
New research led by the University of Washington and the National Oceanic and Atmospheric Administration has revealed how underwater noise produced by humans may help explain why southern resident orca populations have not recovered from historic lows. In a paper published Sept. 10 in Global Change Biology, the team reports that underwater noise pollution — from both large and small vessels — forces northern and southern resident orcas to expend more time and energy hunting for fish. The din also lowers the overall success of their hunting efforts. Noise from ships likely has an outsized impact on southern resident orca pods, which spend more time in parts of the Salish Sea with high ship traffic.
March 10, 2023
Northern and southern resident orcas hunt differently, which may help explain the decline of southern orcas
In the Pacific Northwest and British Columbia, southern resident orcas have experienced no net population growth since the 1970s, with just 73 left at the most recent count. But northern resident orcas, which have a similar diet, territory and social structure, have grown steadily, now numbering more than 300. A new study led by scientists at the University of Washington and NOAA Fisheries may help explain why: The two populations differ in how they hunt for salmon, their primary and preferred food source, a key difference that conservationists will have to take into account when designing interventions to help southern residents.
