The number of gray whales migrating along the Pacific Coast of North America has steadily declined by nearly 40% from a 2016 peak, and the population produced its fewest calves on record this year, according to U.S. research released on Friday.
The 38% drop from the population's 2016 high of 27,000 whales to 16,650 this year resembles previous fluctuations but warrants further attention, the National Oceanic and Atmospheric Research Administration (NOAA) report said.
Researchers at NOAA's Southwest Fisheries Science Center in San Diego said the latest decline, though not fully explained, likely entails several factors including environmental changes that have shifted the whales' food sources of tiny crustaceans and other invertebrates they prey on in the Arctic.
