“Because Fraser river salmon are so temperature dependent, global warming is a threat to their very existence.”
- Doug Chapman
Climate change is the change in weather patterns that a specific region encounters. Globally, the rate of temperature is regulated by the system known as the “greenhouse effect”, where gases such as methane and nitrous oxide absorb and emit radiation. All along this process, the radiation can pass through but the heat is not able to escape. The balance of this natural system has been disrupted by human activities. The more advanced and mechanized human lifestyle becomes, the more production of these gases and hence the increased warming trend all around the globe.
NASA, Fisheries and Oceans Canada, and other organizations’ climate models show warming in the past several years in British Columbia’s Fraser River, with a continued warming trend predicted for the future. This warming is caused by higher and higher carbon dioxide levels in our atmosphere, which is the result of the burning of fossil fuels and other anthropogenic factors, including deforestation.
According to Riverkeeper Doug Chapman: “At times, Burrard Inlet already has depleted dissolved oxygen problems because of the huge volumes of improperly treated sewage being discharged daily by Metro Vancouver from its Lions Gate and Iona sewage treatment plants.”
As the temperature increases, the solubility of oxygen in water reduces. This reduction in dissolved oxygen (DO) threatens fish, amphibians, and cocopods. Less DO causes increased metabolic rates, which can result in faster depletion of food sources and potentially more competition among more adaptive marine life, some of which may be invasive. Fish may become smaller, more susceptible to disease, and malnourished.
Higher water temperatures also increase plant life, which can cause algae bloom, which further reduces oxygen in the water.
The Fraser, currently predominantly a snow-melt river, could become a rain-dominated river, which would cause a change in elevation and flow, with a higher flow in the summer and fall. Any climate change like this will alter how fish reproduce, migrate, and survive.
Water temperatures above 19-20° C are dangerous for salmon and other fish, degrading spawning rates, causing thermal shock, and becoming fatal at around 24° C. Changes in 1-2° C can produce significant cellular changes that are detrimental to cell walls, proteins, and enzyme metabolism.
Global warming causes changing precipitation patterns, increasing evaporation, melting glaciers, and droughts and floods to become more frequent and intense
Any or all of these factors do and would affect the Fraser River and surrounding wetlands. Any unbalance as such would threaten fish and other wildlife on the Fraser. Already, many rivers in the world have been altered by global warming.
There are many industries located along the Fraser River and other waterways around metro-Vancouver such as pulp mills, mining operations, industrial plants (food, wood product, and manufacturing), and oil refineries. The pulp paper industry forms toxic by-products from its industrial activities such as chlorine bleaching and industrial inceration. Examples of these by-products include dioxins and furans, and are known to suppress the immune system function, damage the liver, and bioaccumulate in fish and shellfish, leading to human health risks if consumed.
The lumber industry uses highly toxic chemicals, called antisapstains, which help protect wood from the discoloration caused by fungi and mould. The chemicals can end up in the Fraser River as a result of spills into storm sewers or being washed off treated wood in a rainstorm.
Agricultural run-off is a concern for the Fraser River and its watershed, and can cause short-term, long-term, and cumulative impacts. Agricultural runoff is a non-point source of pollution and can come from various different sources in different locations. The run-off can consist of pesticides, insecticides, fertilisers, and animal manure — and can enter the runoff through atmospheric deposition, irrigation, and crop residues. These biological and chemical substances can be high in nutrients such as nitrogen, phosphorus, pathogens, and a range of other chemical compounds. A rapid growth in agribusiness along the Fraser River has lead to increased pesticide and fertiliser use and farm animal intensities, especially in the Lower Fraser Valley.
Rapid urbanisation in the Lower Fraser Valley has also affected the quality of the Fraser River and its tributaries. Increased infrastructure such as transportation routes and traffic has led to increased surface run-off of pollutants such as hydrocarbons and road-building substances. New development pressures metastasize as the vibrant Vancouver region draws more residents and more economic activity. The Greater Vancouver Regional District now houses more than 2.1 million people. It is expected that in the coming 20 years the population will increase by another 50%.
This growth has detrimental consequences on the watershed due to both the development of surfaces, which exacerbates storm water run-off, and combined sewerage outfalls. There are increased demands upon already inadequate sewage treatment infrastructures and increased indiscriminate waste disposal adjacent to and into the Fraser River and its tributaries. All of these issues can result in surface and groundwater contamination and detrimental longer-term impacts on the biodiversity of the Fraser River Basin.
Sewage pollution from outdated onsite and municipal sewage treatment facilitates are the main contributors to municipal pollution in the Georgia Strait, Burrard Inlet, and Fraser River. In metropolitan Vancouver and the increasingly populated Fraser Valley, municipal sewage pollution contains a large number of toxic substances such as pathogens (bacteria and viruses); nutrients such as nitrogen and phosphorus are also a problem. Increased nutrients in the water can lead to excessive plant growth (such as blue-green algae).
When sewage material decays and algal material grows, they take up oxygen in the water, which is exasperated in the warmer summer months. This process reduces the amount of oxygen available to marine invertebrates and fish at high discharge rates.
Municipal sewage waste can also create potential health risks for recreational users of the waterways. Polychlorinated byphenols (PCBs) were banned from production in the 1970s but are still found in the bottom layers of sediment and can be discharged back to the air. PCBs can affect the neurological, immune, and reproductive systems of mammals and also are known to cause cancers.
The Iona wastewater treatment plant is located in the city of Richmond, just north of Vancouver International Airport. It serves a large portion of the metropolitan Vancouver population. It provides only primary sewage treatment before disposing the effluent in a deep-sea outfall in the Georgia strait. Both the Iona and the Lionsgate treatment facilities require urgent upgrades (see Ottowa Riverkeeper and Eco-Justice).
Also, approximately 150,000m3 of sewage effluent is discharged into the Fraser River Basin from sewage treatment plants located upstream from the town of Langley, close to the mouth of the river. The Hope treatment plant located upstream has only primary, not secondary, treatment of the sewage.
Water pollution in the Fraser River has many sources. Resource-based economic activities located close to the Fraser River include agriculture, mining, logging, and hydroelectric developments. Water quality in the river can be degraded because of these industrial activities, municipal and urban waste water, and individual polluters. Poor water quality affects the habitat of the flora and fauna in the river, and certain pollutants can cause cumulative effects such as pollutant bio-magnification. Excessive nutrient build-up in the river can lead to eutrophication, where bacteria feeding on organic material can significantly reduce the oxygen content of the water and essentially suffocate fish and other fauna.
Known as one of the world’s most important salmon rivers, the “Mighty” Fraser River is also home to hundreds of invaluable species of flora and fauna. Recent salmon spawning migrations have been astonishingly low with many factors thought to be at play, not the least of which is habitat loss and pollution resulting from resource-based economic activities such as logging, mining, hydroelectric development, and agriculture.
The region faces a number of challenges imposed by industries old and new, coupled with the pressures of rapid urban development. Decades of heavy resource extraction and high pollution loads threaten to undermine the rich biodiversity that underpinned the success of the Fraser River Watershed and Vancouver in the first place. Salmon fisheries are depleted, and the future viability of mega fauna like raptors and Orca whales is jeopardized – signifying deeper systemic problems.
Just in the last few years, the declining fish populations have become more worrisome, but in 2009 there was a crisis in the sockeye salmon returns for the summer. Anticipated returns were high, but actual returns, according to the Department of Fisheries and Oceans, were 9-11 million short. This isn’t because of late migrations runs, according to the department, but because the fish died sometime during migration. More studies are underway to determine this loss, but many are speculating some or all of the following to play a role: sea lice and fish farms, over-fishing at sea, global warming, and pollution.
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