Leon Kolankiewicz: Unchecked population growth has downstream effects

Salmon and orca populations in the Pacific Northwest are plummeting.

Chinook, or “king,” salmon populations have declined 60 percent since 1984. And the Southern Resident Orca – a group of killer whales that hunts in Washington’s Puget Sound – now contains only 74 individuals, down from 98 in 1995. Scientists have linked the decline of these species to human development on the Pacific Coast.

As a former fisheries biologist with the National Marine Fisheries Service and the Alaska Department of Fish and Game, I’ve seen how sensitive salmon are to human development – and the pollution and aquatic habitat degradation it inevitably brings. Chinook salmon are healthy and thriving in sparsely populated Alaska, for instance. But in more heavily populated Washington, that same species is considered “threatened” in the Puget Sound.

As adults, king salmon live in the open ocean, but return to spawn in the same rivers where they hatched. In the Pacific Northwest, roads, dams and seawalls all impede the salmon’s journey to its freshwater breeding grounds. Their spawning efforts have been so unsuccessful that, in 2017, scientists monitoring chinook populations caught so few juveniles that they checked for holes in their nets.

To make matters worse, Puget Sound – one of the king salmon’s primary habitats – is permeated with industrial waste – and even spillage from wastewater treatment plants in Seattle, Tacoma and other nearby cities.

More pavement and increased farming have both contributed to an increase in toxic runoff that pollutes the estuary. About 75% of pollutants in Puget Sound came from toxic stormwater runoff.

The current salmon population on the Pacific Coast south of Canada – hanging on at around 1% of preindustrial levels – will never reach the levels it enjoyed before human development in this region. But continued population growth on the Pacific coast could eradicate the many chinook and other salmon stocks forever – and the many aquatic and terrestrial species in the local food web rely on it.

Importantly, in Puget Sound and the Salish Sea, the chinook serves as the primary food source for the Southern Resident Orca. And with salmon populations dwindling, the whales are starving. These orca can eat over 800 salmon per day as a group – but there aren’t enough salmon left in the Puget Sound to satisfy their appetite.

Scientists on the Washington Governor’s Southern Resident Orca Task Force estimate that the king salmon’s population decline is the primary threat to the orca. And without fixes, killer whales could be extinct in 100 years, according to Rob Williams of Seattle’s Oceans Initiative.

Orcas are also battling underwater noise pollution caused by increased boat traffic in the Puget Sound, which makes it harder for the whales to communicate and hunt. Continued noise disturbance can even cause hearing loss. Oil tankers routinely traverse the waterway, raising the specter of a devastating spill.

If Washington’s population continues to rise, so too will the number of boats, roads and dams. Toxic runoff will only increase.

The state population has more than doubled since 1970, growing from about 3.4 million people to more than 7.6 million today. And that figure is projected to exceed 8.9 million by 2040, according to the state’s Office of Financial Management.

In the coming decade, 65% of that growth will stem from “net migration” – both people moving from other states, as well as people moving here from abroad. And in the 2030s, net migration will account for 77% of growth.

This grim future for salmon and orcas isn’t set in stone. Policy changes – from local solutions like zoning reform to national solutions like scaling back immigration – could curb population growth in the Pacific Northwest and preserve the region’s wildlife.

Salmon and orca populations are in crisis. Unless human population growth slows considerably, these wild creatures could largely disappear in the decades to come.

Leon Kolankiewicz is an environmental planner and scientific director of NumbersUSA, a nonprofit organization promoting the recommendations of two Clinton-era presidential commissions on immigration and environmental sustainability.