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.