J39 Chasing a Salmon during an encounter in March, 2017-Photo by Dave Ellifrit
The federal government has stated, “Perhaps the greatest change in food availability for resident killer whales since the late 1800s has been the decline of salmon in the Columbia River basin.”
The Southern Residents currently find themselves in an extremely dire situation due to a number of outside factors. But none has proven to be a greater threat to the continuation of the species than that of a drastic decline in salmon availability. The situation in which the whales now find themselves is equal to that of burning a candle from both ends. As their primary prey continues to decrease, toxin levels stored in their blubber begin to rise. It’s an adverse effect of an already very unfortunate situation that, without proper intervention from those who’ve set these destructive wheels in motion, will only continue to further the species along a path toward complete extinction.
The Southern Residents have relied on Chinook salmon as a primary source of food for generations. The knowledge of where and when these salmon run is something that’s been acquired by reigning matriarchs and passed down for generations. A reduction in prey availability not only affects the whales’ immediate health, but also has long-term effects on the delicate cultural structure that’s helped the population evolve and thrive over multiple millennia. If knowledge is lost or manipulated by outside factors, it can deal a huge blow to a species so dependent on an ingrained social structure.
During the summer months, the Southern Residents prey on salmon in the Salish Sea returning to the Fraser river. During the winter months, they typically prey on salmon near the multiple mouths of the Columbia River. When salmon numbers are lower than normal in the Salish Sea during the summer, the Southern Residents will switch to a “Plan B” and begin preying on salmon returning to the Columbia river. Within the greater Columbia River watershed is the Snake River – a key component in determining the final outcome of the struggling whale population.
Historically, the Snake River was one of the best salmon producing river systems in the entire world. But since dam construction began in the early 20th century, it’s become increasingly troublesome for salmon to complete the already extremely difficult journey from ocean to traditional spawning grounds. The Southern Residents salmon of choice (the Chinook salmon) traditionally spawn at higher elevations in cool water areas along the Snake River – one of the furthest journeys undertaken by the many species of salmon traversing the river system.
The Chinook salmon are large, fatty fish that are a perfect means for gaining the nutrients and energy needed to support large mammals with a tendency to travel great distances throughout the year. But now, in large part due to dam construction, the Chinook salmon have themselves become an endangered species. Without a substantial supply of this nutrient rich food source, the Southern Residents have no other choice but to begin metabolizing fat reserves stored in their blubber, releasing a number of deadly toxins stored up over years of exposure to contaminated water in the process. To make matters worse, recent studies conducted by Washington University have shown a correlation between miscarriages and the reduction of salmon populations. According to their research, 69% of all Orca pregnancies in the Southern Resident population end in miscarriage. Due to a lack of salmon, the majority of sexually mature females are unable to provide the required nutrients to sustain a calf through pregnancy.
Federal agencies and local activist groups have undertaken multiple initiatives to help restore salmon populations. Although actions have been taken to help supply the whales with more salmon – like the release of hatchery fish and the development of more fish ladders along the rivers in question – the majority of scientists and activists tend to agree that the most impactful solution would be to breach the lower dams along the Snake River system. Hatchery fish may seem like a more efficient alternative, but recent studies have actually proven them to be more of a threat to wild salmon populations than a welcomed benefit. It turns out that the DNA of hatchery fish is actually physically different from their wild counterparts. When these two species are mixed and begin mating, the result are offspring that are far less suited for surviving conditions in the wild.
It’s plain to see that without a continuous supply of Chinook salmon from the Columbia River system, there’s little chance that we’ll see the population of Southern Residents restored to a healthy, sustainable number anytime soon. Despite the number of local activist groups and government officials fighting to restore the river to its normal conditions, there is still much to be done. With your continued support, we can ensure that this decades-long battle reaches a prosperous conclusion for our struggling Southern Residents. We encourage you to take action by joining salmon conservation efforts in your area, write letters to your senators, or support groups that fight for Chinook salmon conservation. There are many ways that we can make a difference and we have run out of time to leave it all up to the lawmakers. The whales can't wait any longer.
Sources
http://www.wildsalmon.org/projects/a-lawful-salmon-plan/kuow-northwest-tribes-say-salmon-recovery-is-requirement-based-on-treaty-rights.html
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http://www.idahostatesman.com/news/local/environment/article160452294.html