Puget Sound orcas: Would removing dams save the whales?
After the death of a young female orca and her calf, researchers say that removing dams could mean more fish for whales to eat. But what does that mean for the area?
After the disappearance and likely demise of one young Puget Sound mother orca and her calf, scientists and whale advocates are calling for removing dams that they say could help keep whales healthy and fed.
After the birth of her calf, a rare event in the 80-whale population, 23-year-old J28 took ill and never recovered. Whale experts say diminished salmon availability likely played a role in her death.
“We have drastically altered the availability of the food supply – preponderantly Chinook salmon – both in abundance/biomass and seasonal distribution,” wrote Center for Whale Research senior scientist Kenneth Balcomb in an obituary for J28 and J54, her calf.
The Puget Sound/Strait of Juan de Fuca orca whale pods are known collectively as the Southern Resident Killer Whales, and they were declared endangered in 2005. Over the past 25 years, population numbers have dropped from about 100 to, as of July 1, 80 individual whales.
Orca gestation periods are long, and whales typically live for several decades in the wild. Some of the oldest whales in the world can match humans for their longevity, reaching up to 90 years of age.
What happened to make J28, once a healthy young female, diagnosed as too weak to fight off her illness? What explains the mysterious decline of the Southern Resident orcas?
Dr. Balcomb points to two factors: Human-introduced contaminants to the Puget Sound and the diminished supply of orcas' preferred food, Chinook salmon.
Before she disappeared, J28 was visibly malnourished, as was her calf. Because orcas are pod animals, J28’s sister and older daughter attempted to help out by catching fish and supporting their floundering relatives.
But in the end, it just wasn’t enough.
Whale advocates say that while it is too late to save J28, other Southern Resident orcas can avoid her fate if officials remove dams on the Lower Snake River, which feeds the sound. These dams curtail salmon runs that would otherwise head into the orcas' hunting territory.
"There's no reason these dams couldn't be breached," said Jim Waddell, a retired engineer, at a Seattle press conference on Friday, the Associated Press reported
Those who favor keeping the dams in place say that the dams supply local towns with clean hydroelectric power, and they are important to the region’s economy.
Whale advocates have sought to break down the dams for years. Earlier this year, US District Judge Michael Simon criticized the government’s failure to consider plans to improve salmon populations that included breaking down the dams.
The movement to remove the dams is not without precedent. In 2014, The Christian Science Monitor’s Doug Struck reported on Maine’s decision to open up the Sebasticook river to allow a native fish, the alewife, to run.
In the past six years, alewife populations have rebounded immensely. After the demolition of two dams along the river, 3 million fish are expected to school where six years ago there were none.
Across the country, more than 900 dams have been demolished to return rivers to a wild state.
“We are beginning to recognize the value of what we lost,” says Maine’s Laura Rose Day. “People think dam removals are just about fish. Then they say, ‘Oh, I have more eagles now,’ and ‘Oh, my water quality is better,’ and ‘Oh, I do like the running river.’ ”
But critics point to the human costs of breaking down the dams. In 2007, a study by Pacific Northwest power company Bonneville Power Administration found that removing dams on the lower Snake River was not enough to rehabilitate salmon populations. In addition, the researchers said, switching away from hydroelectric power would cost hundreds of thousands of dollars and require locals to use less environmentally friendly power sources.
Nevertheless, Judge Simon said in May that the solution to the Southern Resident orcas' problems "may well require consideration of the reasonable alternative of breaching, bypassing, or removing one or more of the four Lower Snake River Dams," the Associated Press reported.