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A Dam Big Issue

The Bonneville Dam. While many dams, including this one, provide clean energy, they can block the movement of aquatic animals through the river. Photo via Creative Commons

Salmon populations have been floundering throughout the Columbia River Basin. Pinnipeds, such as seals and sea lions, have been pointed to as predatory culprits for the salmonid struggles. In response to this heavy predation, the US federal government has legalized the selective trapping and euthanasia of hundreds of sea lions per year, in the form of an amendment to the Marine Mammal Protection Act (MMPA). SB 31189, or the Endangered Salmon Prevention Act, was passed in 2020 and authorizes the lethal removal of Steller’s and California sea lions from some locations in the Columbia and Willamette Rivers. However, the project has dealt with significant criticism from those who argue that, rather than blame pinnipeds for the population declines of Columbia Basin salmonids, the government ought to remove the threat that has blocked salmon from thriving in their historic ranges: the dams of the region. These dams, after having provided clean energy and economic benefits to the Pacific Northwest for decades, are having their role in the Columbia River ecosystem called into question.

While a multitude of animals have struggled to adapt in the face of climate change, no class of vertebrates has taken such a nosedive in numbers as fish. Nearly one in three freshwater fish species are at risk of extinction, according to the World Wildlife Foundation.

Salmon in the Pacific Northwest are not returning from the ocean at a high enough rate. A smolt is a younger salmon that heads to the sea for the first of its iconic migrations. Smolt-to-Adult Ratio (SAR) measures the number of smolts that successfully return to their freshwater environments. The Northwest Power and Conservation Council (NPCC) set an SAR goal of two to six percent, meaning that two to six percent of fish return as adults, as a way to sustain salmon populations. A study by agencies including the US Fish and Wildlife service found that in parts of the Columbia River Basin including the Snake River, Chinook salmon and steelhead SARs failed to consistently reach that target, an unfortunate sign for their path to avoiding extinction.

Dams are an obstruction of the territory of aquatic animals. Human development causes headaches for many species, but fish in particular struggle, as they cannot move around the new structures—their mobility is restricted to the river through which they are passing.

Dam developers have made adjustments to their designs in order to better facilitate the movement of fish. However, it becomes difficult to accommodate the unique needs of all fish that attempt to pass through the dam.

Lamprey have had trouble dealing with dams in the past. One particular impediment to their movement was the Elwha Dam, a structure not designed to accommodate any aquatical animal movement, located near the coast of the Northern Olympic Peninsula in Washington. It was designed with “no fish at all in mind. It was an extremely steep canyon,” says Jon Hess, a researcher with the Columbia River Inter-Tribal Fish Commission. “It really cut off passage for a lot of mountainous species and it wasn’t until they could be removed that they had any passage at all for these anadromous [growing up in saltwater and returning to freshwater] fishes.” As a result, fish like Chinook salmon and lamprey were unable to move inland like they normally would.

In 2014, the Elwha Dam was removed over the course of six months, in the largest dam takedown in history. A team of researchers, including Hess, found substantial benefits for lamprey after the dam was removed. They were able to repopulate the area after long being cut off from a large part of their historic range. The study found “robust recolonization” for the lamprey and added that “restoring passage to adequate habitat is a highly effective approach for re‐establishing populations of Pacific Lamprey in coastal systems.”

The dam’s removal also helped salmon. Chinook runs in the Lower Elwha are now growing in population, making it one of the parts of Puget Sound where salmon populations are on the rise, according to the Seattle Times. Removing the dam revitalized the region’s aquatic ecosystem, providing a path of passage for animals that had lost a major route to inland waters.

A Pacific Lamprey. Lamprey have been blocked by dams throughout their freshwater habitat in the Pacific Northwest. Photo via Creative Commons

Dam removal has been questioned as a viable solution due to its long timeline and financial risk. Many areas depend on the energy production provided by dams, which are inseparable from the history of the Pacific Northwest.

Today, nearly 40 percent of Oregon’s energy comes from hydroelectricity. It is the most popular renewable energy source in the United States, accounting for a majority of all renewable energy generated in the country, according to the Guardian. The Bonneville Dam alone provides enough energy to power around 900,000 homes, according to the US Army Corps of Engineers. Hydroelectricity is often touted as an efficient source for a green (blue?) future, and since its energy source—water—is so immediately replenished, hydropower is considered renewable. However, its impact on the environment is not as rosy as some may believe.

One Republican United States House Representative, Mike Simpson of Idaho, wants to remove the dams of the Lower Snake River, not in spite of the fiscal impact, but because of it. Simpson has proposed the Columbia Basin Initiative, a collection of ideas about dam removal. There has not been a bill proposed. Simpson’s goal is to protect Idaho energy and economy. “Despite spending over $17 billion on fish recovery efforts, Idaho salmon and steelhead numbers are not improving and will continue to get worse,” reads the Columbia Basin Initiative website. “Will we spend $20 billion more in the next 30 years only to have them go extinct anyway? The worse they get, the more we will spend.”

Native tribes have been forced to adjust in the face of dam construction for decades, as the American government developed its infrastructure with little regard for existing tribal customs. Celilo Falls, which is now known as the Dalles Dam, is one of the most famous examples in the Pacific Northwest.

Lamprey and salmon are among the most important and oldest food sources for many native tribes in the area. “The Columbia River Treaty tribes are interested in Pacific Lamprey because it is a cultural resource. It has cultural meaning,” says Hess. “It’s one of the first foods for the tribes, so restoring lamprey abundance, or Pacific Lamprey abundance, to the Columbia River is extremely important to the tribes [and] for the [Lower] Elwha [Klallam Tribe] in particular.”

In 1885, the US government signed treaties with four Pacific Northwest tribes: the Confederated Tribes of the Umatilla Indian Reservation, the Confederated Tribes and Bands of the Yakama Nation, the Confederated Tribes of the Warm Springs Reservation of Oregon, and the Nez Perce Tribe. These treaties gave the tribes the right to fish on their reservations and “at all usual and accustomed fishing places,” according to the CRITFC website.

Chinook salmon. Due to dam blockages, heavy predation from sea lions, harvests by humans, and other threats, salmon are in danger of extinction in the area. Photo via Creative Commons

The existing solution for salmon conservation, in parts of the Columbia River Basin, has been to reduce levels of one of the major sources of predation: sea lions. To do so, the federal government has chosen to sanction some trapping and euthanasia. The goal is to keep predators away from the dams, which have made it much easier for sea lions to hunt salmon. Unlike many animals, California sea lions have thrived in the face of climate change. According to NOAA, the number of California sea lions on the American West Coast reached carrying capacity, or the maximum population that can be supported by an ecosystem’s quantity of resources, in 2008, and while there has been some decline since then due to changing ocean temperatures, the populations remain well above any standard of an endangered species.

The euthanasia has been a source of contention, not only because it involves killing animals but also because the pinnipeds may not pose a major threat to salmon at all. A report published on Feb. 28 by the US Army Corps of Engineers estimated that roughly 3% of spring Chinook salmon that attempted to pass through the Bonneville Dam were killed by sea lions in 2020 and 2021. However, measuring predation is not simple, and a report by the state of Washington’s Southern Resident Orca Task Force found that harvest could not account for up to 44% of salmon lost above the Bonneville Dam before reaching the dam, and pinnipeds were attributed as one potential cause. Through development, hunting, fisheries, and their other anti-environmental actions, humans kill salmon at an astronomical rate compared to pinnipeds. 

The program has not led to the euthanasia of many sea lions. Rob Anderson, a marine biologist with NOAA Fisheries and the West Coast Region Program Manager for the Section 120 program, says that fewer than 100 sea lions have been euthanized total through the first few years, though this number was in part impacted by the COVID-19 pandemic. 

Conservationists have found alternatives to removing dams and predators that have helped to revitalize fish populations. One effective method has been translocation, where the fish are moved over the dam to a safer place.

There have also been attempts to prevent pinniped predation without killing them. “Hazing and even relocation of sea lions” were attempted in the past, says Michelle Dennehy, Communications Director for the Oregon Department of Fish and Wildlife. However, “neither worked,” as “sea lions kept coming back to [the] same places.” Hazing involves attempting to intimidate animals through nonlethal tactics, often using seal bombs, which are loud explosive charges, and firecrackers.

While sea lion hazing and euthanasia may not be as effective as some would hope, dam removal may not be the best option, either. Even the fiscal benefits could prove too little, given the timeline. If dam removal efforts were successful, says Anderson, “that could be 25 years down the road by the time that everything was in place to start the dismantling of those structures.” Limiting the damage inflicted by sea lions could serve as an easier short-term solution. “In the meantime, you’ve got something that is a pretty clear threat that is a little easier to deal with,” adds Anderson. “It needs to be dealt with.”

The preservation and protection of salmonids is a priority for many and there are a variety of different approaches proposed to solve this problem. Both dam removal and euthanization of sea lions have their drawbacks and will continue to be a point of contention for all those involved. For now the Endangered Salmon Predation Act continues to stay in place.

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