Despite Ship Strikes, California Blue Whale Population Recovers

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Much has been made about efforts to reduce the number of endangered whales killed by collisions with ships off the California coast. While those efforts are commendable, a new report says, such ship strikes do not immediately threaten the recovery of the California blue whale, the largest animal on Earth. University of Washington researchers say the California blue whale population, which had been decimated by decades of hunting, has rebounded to near historical levels. The whales number about 2,200 today, up from a low of 951 in 1931, according to Trevor Branch, UW assistant professor of aquatic and fishery sciences. “Whaling caused the drop, and was then banned in 1966. Illegal Soviet whaling continued until 1971 when all whaling ceased" for blue whales, Branch told NBC News via email. "Since then the population has been recovering steadily.”

Other groups have estimated that at least 11 blue whales are struck a year along the U.S. West Coast. The UW researchers calculate that there could be an eleven-fold increase in vessels before there is a 50 percent chance that the blue whale population will drop below what is considered "depleted" by regulators. "The recovery of California blue whales from whaling demonstrates the ability of blue whale populations to rebuild under careful management and conservation measures," Cole Monnahan, a UW doctoral student in quantitative ecology and resource management, said in a statement.

Cole is the lead author of the paper published online Friday by the journal Marine Mammal Science. Branch and André Punt, a UW professor of aquatic and fisheries sciences, are co-authors.



— James Eng