Salmon are an iconic species here in the Pacific Northwest. The only image more magnificent than a salmon jumping from the water is an image of a salmon flying towards a bear’s mouth. As we approach the tail end of salmon migration in the Rogue, let’s take a look at how these species interact.
An adult black bear avoids another bear by quickly climbing a nearby tree.
Oregon is home to the black bear (Ursus americanus)– populations are estimated around 25,000-30,000 bears throughout the state. Black bears are omnivorous (eating plants and animals), and although they will eat salmon if they come across it, they do not have a specific connection or adaptation to feasting on these delicious fish as we know of other bear species. Black bears are opportunistic hunters, and they most often fill their diets with nuts, berries, and insects, although an occasional carcass may be consumed. These bears will roam their territory and usually avoid human contact whenever possible. Most human-bear conflicts are a result of their strong sense of smell, which is seven times more powerful than a bloodhound. Bears also remember every location they found a meal, so they often revisit campsites or unprotected waste sites out of habit. This means that one careless human leaving food out can attract a curious bear and create problems in that area for years to come.
Black bear cubs hanging out in a tree waiting for mom to come back.
Grizzly bears (Ursus arctos horribilis) are a subspecies of brown bears and are native to the state of Oregon, but they were hunted to local extinction by the 1930s. Even if you see a brown colored bear in Oregon, it is still a black bear. In fact, black bears can be a variety of colors from cinnamon to brown to deep black. In the United States, Grizzly bears can be found in Wyoming, Washington, Idaho, Montana, and Alaska (the largest population by far). This species currently persists in about half of their historic range. Particularly in Alaska and British Columbia, humans are fascinated by the ecological relationship between these bears and salmon. Both species are incredibly important and have complex interactions. Salmon are known to directly impact their ecosystem through their natural life cycle. As these species spend years in the ocean, their return to freshwater streams and rivers brings an influx of nutrients. They lay several thousands of eggs, most of which end up as a meal for birds, other fish, and semi-aquatic mammals. Once salmon spawn, they die, and those nutrients are reabsorbed into the surrounding forests and floodplains. Before they can reproduce however, many salmon have to pass through a gauntlet of hungry bears.
Salmon migration in the fall corresponds with a bear’s need to fatten up for the winter. During October and November, bears are going through hyperphagia, which means they have an intensive and excessive need to feed before entering hibernation. As mentioned earlier, bears remember where they have found previous meals. So once they find a high energy salmon run area, they will return year after year to take advantage of the congregation of fish. During peak salmon runs, there are plenty of fish for all the local bears, but there can occasionally be conflict between bears (or dominance displays) if their meal is threatened. You’ll often see submissive bears take their catch into the woods to avoid unnecessary aggression. Bears are also taking advantage of multiple spawning runs– so they can move to different streams and catch multiple migration events. This process feeds bears, but it also has other benefits. The remnants of their meals are left for scavengers, the nutrients are taken up by riparian vegetation, and salmon populations are managed. At least, that’s how it’s supposed to work– continued declines of salmon populations threatens this natural cycle.
Brown bears fishing for salmon in Katmai National Park, Alaska.
Although we don’t often get to see this iconic duo in action in Oregon, we do see the benefits of salmon getting upstream into our watersheds. Salmon runs are in decline, particularly in the continental portion of the Pacific Northwest. This greatly affects Native American cultures that historically relied on these migration events for food security. Restoring these species not only benefits Indigenous peoples, it also improves ecosystem health, generates economic activity, supports other aquatic & terrestrial species, and allows for increased recreation opportunities.
Our work in the Rogue River watershed is closely aligned with recovering native Coho and Chinook populations. These keystone species are vital to the health of many ecosystem components, so if we are able to recover salmon populations, we also know that other aspects of aquatic systems will bounce back. If salmon decline further and reach local extinction, other wildlife populations in those systems will likely follow. Learn more about how our projects are helping to recover these iconic species here– featuring our work in the Wild & Scenic Elk Creek.
Group of coho salmon (and a few pink salmon) migrating upriver,
photo courtesy of Eiko Jones.
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