Orcas, salmon, and the Pacific Northwest

Salmon have lived in the Pacific Northwest for millions of years diversifying into different species: Pink, Coho, Chum, Sockeye, and the largest of all Pacific salmon — Chinook. To better understand the relationship the Southern Resident orcas have with salmon, we need to travel back in time. About 13,000 years ago, the last glaciers that carved out our majestic mountains had finally receded. They left in their wake furrowed land that was rich with moisture, glacial sediment, smooth broken stones, and fresh cold water that would form our rivers. The abundance of moisture in the soil gave birth to the towering trees and native plants that shade, filter, stabilize, and oxygenate the riverbeds to this day. Salmon that had retreated further south during the last ice age re-expanded north to newly created spawning habitat. For the last 13,000 years, the clean, covered, nutritive cold water with smooth rocks to shelter fertilized eggs has allowed these fish to thrive.

Georgia Strait Alliance

The temperate forest ecosystem of the Pacific Northwest developed into one giant living biological organism with rivers serving as the arteries and veins transporting the red blood cells—salmon—upriver where they spawn the next generation of salmon. This giant inland organism evolved around the presence of Pacific salmon. Over 200 species of plants, birds, and mammals (terrestrial and marine alike) depend on salmon for survival. Once salmon have reached their spawning grounds, bears and eagles pluck adult salmon from the river to eat, often leaving the nitrogen, carbon, and phosphorous rich carcasses behind on the forest floor where they provide nourishment to the giant Douglas Firs and Western Hemlock trees. In return, these towering trees shade and protect the river, making it habitable for fish.

Sockeye Salmon in the Adams River, Department of Fisheries and Oceans Canada

As salmon migrated across the northeast Pacific for thousands of years, some of the ocean’s top predators, orcas and pinnipeds, evolved with them. Pinnipeds, such as harbor seals and sea lions, eat a wide variety of fish aside from salmon including rockfish, herring, smelt, and squid. Today, as large numbers of pinnipeds inhabit the coastal waters of the north Pacific, one major ecotype of orca—known as the Transient killer whale — is also flourishing. Transient killer whales travel in family pods made up of five or six individuals, usually a mother and her offspring. They occasionally group together with other pods of orcas, related or not, in order to reproduce, socialize, and hunt. The diets of these killer whales also include other large whales and porpoises.

The Resident ecotype of killer whale thrives off the nutrient-dense, forest-fed waters off the Pacific West Coast. Two distinct communities with somewhat overlapping territories exist in Canada and the U.S., Northern Residents and Southern Residents. Both rely on salmon—mostly Chinook. Southern Residents are the main focus of Whale Scout’s programs and are made up of 3 matrilineal family pods (J, K, and L pods). Yet a third ecotype of killer whale exists in the Salish Sea: Offshore killer whales. Rarely seen, these whales are thought to eat mostly sharks, and as a result have worn-down teeth from the rough skin.

Over the last 150 years, Europeans developed the Salish Sea watershed for large-scale human habitation. We didn’t understand how our actions would alter the life of the majestic forest and sea surrounding us. Forests were cleared, beaches were walled up, and rivers were dammed to allow western civilization to flourish. Commercial fisheries were established to bolster the economy and the orcas were seen as vicious, voracious fishing competition. Our Western scientific understanding of killer whales was non-existent. Out of fear and misunderstanding, humans shot to kill orcas as recently as the 1960s.

Beginning in the early 1960s, the marine park and aquarium industry was booming and began to target killer whales in Puget Sound. Capture teams patrolled Puget Sound by air and boat, searching for orcas. When a pod was located, the teams chased the whales into coves, often detonating underwater seal bombs to disorient and frighten them, making it easier to corral the group into a net pen and separate and remove the calves to be sold for captivity. It is unknown exactly how many whales were taken, but federal estimates put the number at around 50 individuals—mainly Southern Resident J and L pod individuals. The last living captured Southern Resident orca named, "Lolita" passed away in 2023 at the Miami Seaquarium at the age of 57.

Members of L pod captured in Penn Cove, Wallie Funk, Associated Press

In 1976, the horrific capture of a Transient orca pod (including the still wild-living matriarch T46) at Budd Inlet was witnessed by Ralph Munro, who, at the time, was an aid to Washington Governor Evans. Motivated by the horror of what he saw, the capture process was later outlawed in the state of Washington. As a result, the federal government hired biologists to study, count, and track local orca populations. Scientists, such as Michael Bigg and Ken Balcomb, began to learn about the vibrant lives and cultures of the Salish Sea orcas, and our fear of these northwest icons was replaced with awe.

As Ken Balcomb continued monitoring the orca population, he discovered that resident population numbers mirrored that of the salmon returns. In years when the salmon runs were strong, the resident orca population boomed. When the salmon runs were weak, more resident whales died. In 2005, the Southern Resident killer whale population were listed as endangered under the Endangered Species Act following a precipitous drop in numbers. Today, Southern Resident killer whales number fewer than when they were listed as endangered, a disappointing trend. The main cause of this decline is a lack of salmon.

Annual indices of mortality of (a) northern and (b) southern resident killer whales and (c) abundance of Chinook salmon, 1979-2003. Deviations from an annual index value of 1 (a,b) indicate higher or lower than expected mortality rates. Annual abundance indices for Chinook salmon (c) reflect departures from the average abundance over the entire time series. Ford et al., 2009

A well-fed orca has a thick layer of fat, also known as blubber. Aside from providing buoyancy and body heat control, the blubber layer is where an orca stores ingested pollutants. As top predators with long lives, any pollutants in the water (PCBs, DDT, flame retardants, etc.) bioaccumulate at the upper levels of the food chain. Well-fed orcas store the pollutants in their blubber layer where their side effects are minimal. The Transient orcas of the Salish Sea have an abundant supply of pinnipeds and other marine mammals to feed upon and therefore are able to keep toxins stored away in their blubber. The Southern Residents, despite eating lower on the food chain (marine mammals vs. salmon), are more at risk to toxin exposure since they are metabolizing their blubber stores and burning fat during times of low salmon abundance. These toxins are proven to disrupt immune and reproductive systems. Compounding these issues are vessel impacts. Underwater noise disrupts the whales' echolocation and communication.

Lack Of Salmon

Local endangered killer whales (orcas) rely on dwindling salmon populations for 90% of their diet


Lubricants, coolants, and flame retardants are linked to disease and reproductive issues.

Vessel Effects

Vessel noise impairs killer whales' ability to echolocate their already diminished prey.

To recover these endangered Southern Resident killer whales we must address these three main threats. Whale Scout’s programs address each one and provide ways for you to get involved. First, we offer ways to watch whales from shore without leaving any trace on our waters. Second, we help limit toxins from entering our waterways. We offer suggestions each month to become better stewards of the environment, which add up to help the whales. Our volunteer events also limit toxins from entering our waterways through the natural treatment of stormwater runoff. At these events we plant trees and work to restore ecological function along salmon rivers, streams, and nearshore habitats. This provides salmon more places to live, spawn, and thrive. The more salmon there are, the more food killer whales have to eat. No matter where you live, you can make a difference with PodMatch, through your donations, or via participation with groups throughout the west coast.

We must keep in mind that we’re striving for intact ecosystems from the treetops to the outer coast. Not only will the whales benefit from resilient forests, rivers and streams, everyone else will too, including us. The work we do restoring salmon habitat results in cleaner water, air, and more salmon for everyone.

Southern Resident killer whales have a broad range from Southeast Alaska to to Monterey, California. Some of these West Coast rivers extend hundreds of miles inland crossing the backyards and neighborhoods of major population centers. Unfortunately, many of these populations of salmon are also threatened or endangered.

What’s the Connection Between Planting Trees and Saving Whales?

A significant amount of time spent at volunteer work parties involves restoring the "riparian zone," or vegetation immediately along salmon rivers and streams. You may ask, “Why is this important, and how does it help?” Well, with the help of our friends at the Skagit Fisheries Enhancement Group, we came up with a fun way to remember: 6 C's Thanks to Trees!

Trees improve important water quality features that salmon need to thrive.


Trees shade the water, keeping it cool in warm months


Vegetation and root systems filter toxins in rain runoff before entering into waterways


Complex root systems hold the banks of rivers and streams, preventing erosion which can smother salmon eggs


Consistently flowing waters are critical for salmon. Rushes and low drops in water levels don’t allow fish to move where they need to go or can scour out eggs embedded in streambeds. Rain is slowed down by tree branches and is stored in the ground beneath trees to slowly be released into the main channel.


The tiny bugs that baby salmon need to eat live on native vegetation. This gives the orca’s food’s food a place to thrive!


Towering trees and fallen logs offer adult migrating salmon some protection and refuge from predators such as birds who may be lurking above.

The Nature Conservancy

Additional Links & Resources

Alaska Department of Fish and Game - Salmon and Trees

National Geographic - Blubber

Orcas in Our Midst

The Olympian - Orca Captures

NOAA Spotlight on SRKW