According to experts, the reason for the starvation in the Southern Residents is most definitely a lack of salmon, which make up the largest and most nutritious part of their diet. Wasser and his fellow researchers found that levels of thyroid hormones were lowest in the Southern Resident whales following known drops in Chinook salmon from the Fraser River, while increases in salmon in the river were associated with increases in thyroid hormone levels.
In the past 10 years, salmon — particularly those spawning in the Columbia River — have decreased. While that’s certain, Wasser said what’s not well understood is why their numbers are dropping. Overfishing and habitat loss due to development could play a role in the fish’s demise. However, it appears more likely that the construction of hydroelectric dams on rivers where salmon spawn and migrate are to blame.
“Some say dams are key, including the Snake River dam, which impacts levels of early spring Chinook, some of the fattiest fish known and essential to replenish whales from the harsh winter and sustain them until the Fraser River Chinook run peaks in the summer,” said Wasser.
Giles takes a stronger personal stance when it comes to discussing the threats to survival the Southern Residents face. She said it’s clear that fishing restrictions and dam removal are necessary in order to replenish salmon and killer whale populations in the Pacific Northwest. But making her voice heard has been something she’s been criticized for doing as a scientist.
“I won’t stop telling the truth about what’s happening just because it’s politically ‘incorrect’ or unpopular,” said Giles. “We need to take action now or we’ll lose these genetically and culturally distinct whales forever.”
Whether we succeed in doing what is necessary to help this population survive, or whether we let them dwindle away, is a true test of whether anyone really cares enough about the rest of the species on this planet. Everyone says they love killer whales. But if they can’t be mobilized to help a species they love, then what hope do all the other species have?
Seventy-percent of pregnancies are resulting in miscarriage, estimates one study. And the scientists behind the report believe they know why:
Over the years, killer whales accumulate toxins from their food in their fat. Normally, these pesticides and chemicals, such as PCBs or DDT, have chronic effects on the whales. But in recent years something else has happened: chinook salmon—one of the whales’ most important food sources—have dwindled.
When the whales don’t get enough to eat, they start to burn their fat reserves, which releases the stored toxins into their bloodstreams. This hurts the health of the developing calf, and the effect is particularly pronounced late in the pregnancy when the fetus is growing rapidly.
“The cumulative effects of loss of food and release of toxins are the best predicators of whether or not a pregnant female will take a fetus to term or abort it,” Wasser says.
If that is right, then the only way to boost the chances that this endangered population will survive is to rapidly boost populations of their favorite food, Chinook salmon. That isn’t easy, but breaching dams where Pacific salmon spawn, allowing greater numbers to get upriver and reproduce, is one key step supported by researchers who study the Southern Resident killer whales.
NOAA disagrees, but at this point it seems clear that more radical and creative solutions are required if there is to be any hope of supporting the remarkable population of killer whales that reside in the Pacific Northwest–who unfortunately occupy a habitat that is deeply impacted by human activity from pollution, to shipping, to fishing (not to mention a decade of captures). We are responsible for their troubles. We should feel a moral obligation to do what is needed to reverse their decline.
The native peoples of the Pacific Northwest understood something important about the relationship between the region’s iconic killer whales and the region’s iconic salmon. The first could not survive without the second. “No fish, no Blackfish” they observed.
That observation is in danger of proving prophetic. As the Center For Whale Research’s Ken Balcomb warns, lack of prey food is threatening the demise of the endangered Southern Resident Killer Whales. The SRKW population is under pressure for a number of reasons–shipping, noise, habitat loss and pollution, among them. But Balcomb is warning that the most clear and present danger is hunger resulting from declines in the Pacific Northwest’s great salmon runs, mainly due to the damming of rivers. Currently, Balcomb and others are calling for breaching four dams on the lower Snake River which have devastated the region’s once-prolific Chinook salmon runs. And for compelling evidence of what is happening he points to the recent deaths of a mother killer whale and her calf, both of whom were evidently malnourished.
For the data-inclined, here is a chart that looks at the correlation of SRKW mortality and Chinook abundance.
The tension between dams and killer whales is just one more reminder of how closely connected different ecosystems can be, and the endless consequences for the natural world of human development. Dams may provide “clean” hydropower, but they do so at the unacceptable cost of destroying and damaging entire river systems and the species that rely on them. Wind and solar have impacts, too, but they are more local and limited.
Removing dams is one of the most promising environmental trends. And when you take dams down and allow rivers to flow freely again, remarkable things happen. Whether the Snake River dams will be breached in time to save Washington state’s killer whales involves an excruciating race against time and hunger. Even the courts are pushing hard on this issue. But Ken Balcomb, who has been studying this population for 40 years and knows more about these killer whales and what they need than anyone on the planet, is pretty clear that if dam breaching is going to happen it better happen very, very soon.