Short Wave We saved gray whales from extinction. Why are so many dying again?
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Mar 11, 2026 
Joshua Stewart, a marine ecologist at Oregon State University who studies marine mammals and Arctic benthic ecosystems, joins to unpack repeating mass gray whale deaths. He describes historical boom-and-bust mortality patterns. He traces the shift from disease hunts to linking whale declines with Arctic prey cycles and climate-driven food shortages. He considers limits to human intervention and whales as climate warning signs.
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Recovered Gray Whales Hit Dramatic Boom And Busts
- Gray whale population shows unexpected boom-and-bust cycles after recovering from whaling.
- Joshua Stewart found 20–30% die-offs in a few years despite whales being long-lived and slow to reproduce, which is surprising for such a species.
Arctic Benthos Data Matched Whale Die-Offs
- A colleague's Arctic benthic data lined up perfectly with whale declines and recoveries.
- Jackie Grebmeier's long-term benthic grabs showed prey biomass cycles that matched gray whale booms and busts almost exactly.
Recovery Made Whales Vulnerable To Prey Fluctuations
- Once gray whales recovered to carrying capacity, competition made them sensitive to prey fluctuations.
- Joshua Stewart explains populations at high abundance suddenly feel small changes in Arctic food availability, causing big population responses.