Puget Sound Orca Poop is a 'Treasure Trove' for Researchers
Topics: Biodiversity, Biology, Environment
SAN JUAN ISLANDS, Wash. — Puzzled by orcas’ failure to thrive in Puget Sound, researchers have turned to a secret weapon with a killer nose.
Scientists have several hypotheses for why Puget Sound killer whales are not recovering after being added in 2005 to the federal list of endangered species. They suspect lack of food, vessel traffic and pollution are to blame, but no one knows for sure.
Researcher Sam Wasser and his team are finding answers in the whales’ wake. Or, more specifically, in the fecal matter they leave behind as they swim through the waters of Puget Sound.
“It looks like a combination of algae and snot, if you want to know the truth,” explains Wasser, the director of the Center for Conservation Biology at the University of Washington. “It varies in color but it’s very mucusy.”
But Wasser says poop’s not gross. It’s scientific gold.
“We can measure the diet of the animal, we can get toxins from the feces, DNA so we can tell the individual’s identity, it’s species, sex and all of this is in feces. So it’s literally a treasure trove of information,” says Wasser.
His team has developed techniques to analyze animal poop from all over the world. His center has helped prosecute ivory poachers in Africa, track wolverines in the Rockies and better understand predator-prey interactions between wolves and caribou in the tundra.
But finding wild animal poop, especially whale poop, isn’t easy, so Wasser has taken a creative approach to staffing his organization. Wasser looks down lovingly at his furry black sidekick.
“This is Tucker our scat detection dog. Say hi Tucker.”
Tucker is an 8-year-old black Lab mix. He’s what those in the dog world call “ball obsessed.” Tucker will do anything for a game of fetch – even if that means sniffing out floating whale poop from a mile away – because he knows that when he finds the poop he gets to play with his ball.
Killer whales have been found to have the highest concentrations of toxic substances like DDT, flame-retardants and PCBs of any creature on the planet. Jessica Lundin, a graduate student at the Center for Conservation biology, says that if scientists can understand more about the contamination in these animals, they may be able to explain why they’re not recovering.
“These toxicants have been shown in the lab to have reproductive impairment, thyroid disruption and to be immunotoxic. Those are very concerning attributes, especially when we know this endangered population has incredibly high levels.”
I join Wasser and his team as they head out of their base, San Juan Island’s Snug Harbor, in search of poop samples. As we’re rounding a rocky outcropping another research pipes in over the radio with the identification numbers of a pod of killer whales spotted passing nearby North Pender Island.
Deborah Giles, a PhD candidate at the University of California Davis and an expert on killer whale behavior, notes down the location and steers the boat. White caps slap at the bow as we pick up speed.
But we’re rewarded when black dorsal fins emerge several hundred yards ahead of us.
“There they are!” Giles exclaims. “They’re at 11.”
Liz Sealy, Tucker’s trainer, is in the bow of the boat with the dog trying to pick up a scent as we criss-cross the waters where the whales last surfaced – on the lookout for poop.
“When he gets excited he’ll start standing up on the bow, wagging his tail, getting really animated. So for now he’s just checking the scene,” she explains.
Tucker wanders back and forth across the bow but doesn’t seem too excited. The researchers spend about 20 minutes bobbing along after the whales, but alas, Tucker comes up empty-snouted. The winds are too strong and the water’s too rough for him to lock onto a strong scent.
Despite this unlucky mission, the team will continue to collect samples from killer whales in these waters throughout the summer.
With samples collected in the past, Wasser’s team has been able to show that during periods of high vessel traffic – say Fourth of July weekend for example – the whales have higher levels of stress hormones in their poop. Combine that with smaller runs of Chinook salmon, which the whales prefer, and you’ve got problems.
“The data suggests that at times of low prey abundance there’s a cumulative impact of boat traffic. The whales are more stressed,” says Katherine Ayres, a graduate student with the Center for Conservation Biology. The researchers can also tell when the whales are undernourished and correlate that with lower fertility rates and higher mortality.
There are about 86 resident killer whales in the region and that number hasn’t increased since 2000 when the population crashed. Wasser suspects that the toxic chemicals in these whales may be playing a role here because they disrupt major hormonal pathways.
“They disrupt major hormonal pathways so that your body’s ability to regulate reproduction, metabolism all those things can be negatively impacted,” he says. “It’s accumulating effects that are occurring and we’re just trying to show the mechanisms that lead to that outcome.”
For Deborah Giles, that outcome is pretty clear. “There are females that haven’t had calves yet and really they should have been having calves by now. Also we’re losing males that are just coming into reproductive age. That’s a huge hit to this population.”
It’s tricky to pick apart the various factors that make life tough for orca whales. Lack of food, vessel traffic and toxic pollution all pose a threat to these animals but by studying poop, scientists can look at all these things collectively — providing some direction for policymakers who are trying to solve human global health problems.
Wasser says a sample of whale poop is kind of like a snapshot of pollution levels in our coastal waters and that’s a photograph we might all want to have a look at.
EarthFix is a public media project of Oregon Public Broadcasting and Boise State Public Radio, Idaho Public Television, KCTS 9 Seattle, KUOW Puget Sound Public Radio, Northwest Public Radio and Television, Southern Oregon Public Television and the Corporation for Public Broadcasting.
See the related Video, Science on the SPOT: Sound Waves – Listening to Orcas:Tags: dog, killer whales, noise pollution, orcas, poop, salmon, stress, toxins