New research shows orcas in local waters are stressed because of a lack of salmon more than because of whale watching boats or toxins.
Scientists analyzed hormonal responses to stress that were measurable in whale scat, or poop.
A black Labrador Retriever named Tucker sniffs for scat -- a scent he's been trained to recognize as the fishy smell distinctive to southern resident killer whales.
"Our dogs can locate killer whale scat, can smell it over a mile away, regularly," said Sam Wasser, a University of Washington professor of biology.
Wasser, the "Guru of Doo-doo," and other researchers at the Center for Conservation Biology, have been gathering fecal samples, analyzing hormones in them to try to find out what may have caused a decline in the late 1990's in the number of orcas that visit Northwest Waters every summer.
"We learned that fish is all-important," Wasser said.
What his team has discovered is that nothing stresses orcas more than a lack of their main meal, Chinook salmon -- not boats of whale watchers or toxins such as PCBs that have entered their tissues.
"What is clear to everyone is that we need to increase the total amount of fish," Wasser said.
It's not just the fish in Puget Sound waters, but the spring runs of Chinook that whales eat on their way to San Juans, possibly those that spawn in the Columbia River system.
That's why Wasser suggests taking another look at dams on that river that block fish passage to additional spawning habitat.
"Of course, taking a dam down is a huge deal, and we don't want to do that until we are very sure. But what is clear from this work is that we really need to look at that."
KIRO
