Over the years, scientists have identified dams, pollution, and vessel noise as causes of the troubling decline of the Pacific Northwest’s resident killer whales. Now, they may have found a new and more surprising culprit: pink salmon.
Four salmon researchers were perusing data several months ago on the website of the Center for Whale Research, which studies the orcas when they noticed a startling trend: that for the past two decades, significantly more of the whales have died in even-numbered years than in odd years.
