Comparing Streams in Southwest Washington to Determine the Needs of Salmon
Part of the Young Naturalist Awards Curriculum Collection.
"If you gave me several million years, there would be nothing that did not grow in beauty if it were surrounded by water." -Jan Erik Vold
Water is a large part of all living things. In creeks, organisms depend on water for survival. I wondered what salmon needed in order to survive in their habitat. I wanted to know why there hasn't been a large salmon run in Salmon Creek since the early 1900s. I know that back then there weren't many homes along Salmon Creek, but now there are more homes along the bank. I fear Salmon Creek is becoming polluted. I wanted to find out what the basic needs of salmon are by comparing local streams in southwest Washington, some of which have healthy salmon runs. I could then see if the salmon's needs were being met at Salmon Creek. The three streams I'm going to study are: a 20-year-old stream located in the Pumice Plane near Mount St. Helens; Cedar Creek, an established creek that has returning salmon runs; and the headwaters and lower reaches of Salmon Creek. I'm going to be looking at the habitat around the creeks and the condition of the creekbeds. I'm going to be taking notes on the pH and conductivity levels of the water. I'll also measure its temperature. If the water is too warm, then the salmon will die off.
August 8, 2002: It's a beautiful August morning and my brother is driving along the windy roads to the northeastern slope of Mount St. Helens. After a two-hour drive we pull into the Windy Ridge parking lot. As I get out my tools, a cool breeze ruffles my hair. We make our way down the loose pumice trail toward the Pumice Plane. I look at my thermometer. It shows 22°C. The cool wind catches the fragrance of purple prairie lupine flowers that line the trail. Lupines provide shelter for insects like grasshoppers, which make a telltale rat-tat-tat sound as I walk by. The lupines also provide food for hundreds of butterflies, which flutter around me like gems in the golden sunlight. I recognize West Coast lady, Boisduval's blue, and ruddy copper butterflies feeding along the trail.
As I make my way through the desert-like surroundings of the Pumice Plane, the aroma of lupine is gone. I hear the sound of water trickling. Down on the bank I see a small stream with arroyo willow (white willow) and other plants growing alongside. White willow is a tall, jungle-like tree with brown bark that covers the stream with shade. The bank is also covered with pink monkey flower plants that bees land on so they can collect the nectar and convert it into honey. The streambed's rocks are covered with an emerald-green moss that grows in the refreshing 7°C water. I take a water sample to be tested later on. Further down the stream I find some long, slimy moss waving in the steady current. Even though there are no salmon in the stream, it's bringing life back to Mount St. Helens.
The sun is hot overhead, and dust blows into my eyes. I look out across the horizon. I can see rows of white willow growing towards Spirit Lake. Each row represents the beginning of a new creek. The grasshoppers and butterflies flutter out of our way as we head back up the pumice trail, and the sun sinks behind us.
August 28, 2002: At 9:40 on this August morning, I am making my way up the moist dirt path toward the rushing water of Cedar Creek. As the path widens, I see where the Washington Fish and Wildlife Department has set up a fish trap to catch fish, which they count daily. I continue on the path, and a sticky spider web breaks across my face. I reach the edge of the bank, where the 2- to 3-foot-deep water is moving very swiftly. I take the water temperature: 18°C. I take a water sample, too. There are boulders scattered along the bank. Some are too large to see over. Cedar Creek is shaded by fir trees, alder trees, ferns, and other bushes. The boulders at the edge of the creek form pools that black water skippers, periwinkles, and mayfly larvae live in. The animals in the pools provide food for salmon.
I climb over one of the large boulders and move 200 yards upstream. The water is much calmer. The bottom of the creek has gravel, sand, and pebbles for salmon to build redds in. Redds are gravel nests made by the female salmon for her eggs to be laid in. As the water pours gently over the shiny rocks, I spot a brown trout about 1 1/2 inches long swimming along the edge of the water. I climb back over the slick rocks to the dirt path. As I walk down the path, I see three more brown trout and two red-orange crawdads picking their way through the gravel.
August 28, 2002: At 11:45, I'm at the lower part of Salmon Creek located in Hazel Dell; there are a lot of new homes being built around this part of Salmon Creek. An asphalt path follows along the edge of the grassy bank. The bank is covered with tall grass, a few scattered alder trees, and a hedge of blackberry bushes. I find an opening in the grass that leads to the creek. Once at the bank I tie my thermometer on to a fishing line and cast it to the middle of the creek to get an accurate temperature. After a while I pull the thermometer out of the water. It shows 22°C. I take a water sample. As I examine the murky water, I notice the creek bed is muddy, which is not good for salmon to lay their eggs in. The mud does not protect the eggs from the force of the water, or allow the freshwater to bring them oxygen, as gravel beds do. A movement catches my attention. I see two baby brown trout chasing each other and a four-inch-long red-orange crawdad.
September 24, 2002: It's 5 pm as I climb over large logs and tall grass and slog through the quicksand-like mud. The sun begins to set over the treetops. I am at the headwaters of Salmon Creek. As I get closer to the shady bank, there are blackberry bushes, horsetails, alder trees, and grasses on either side. The pebbly bottom of the creek is home to water skippers, mayfly larvae, and periwinkles. Today the headwaters are 15°C.
December 8, 2002: As I walk along the bank of Salmon Creek behind my house looking for salmon runs, I notice a two-inch-thick layer of foam at the edge of the bank. I wonder where the foam is coming from. I decide to go further upstream to find the source of the foam. I travel to the headwaters of Salmon Creek and make my way down the steep mud path to Salmon Creek falls. At the edge of the waterfall I find the same foam. I go further upstream to find the source of the foam, and see more of it. I think the foam is coming from a house at the beginning of the creek that is dumping something into the water, or perhaps the foam is caused naturally.
At each location I took a water sample for testing at a local laboratory. I tested the four water samples for conductivity, or the amount of dissolved minerals contained in the water, and pH. Of the four samples, the lower part of Salmon Creek had the highest conductivity. It had a conductivity of 187 µsi (µsi means micro-Siemens/cm; the higher the conductivity of the water, the more dissolved minerals are in it). Car soap, fertilizers, and oil dumped into the creek could possibly have caused this. The second highest conductivity was from the Pumice Plane. It had a conductivity of 95 µsi, most likely from the dissolved volcanic materials in the water. Cedar Creek had a conductivity of 86 µsi. The headwaters of Salmon Creek had the lowest conductivity because there are fewer houses along its banks and it's an established creek.
In all four creeks/streams, the pH was within a tolerable range for spawning. The headwaters of Salmon Creek had 6.85 for its pH. Lower Salmon Creek's pH was 7.38. Cedar Creek was 7.06. The lowest pH was Pumice Plane, with 6.27; this was slightly less than normal, which could be due to the acidic nature of the volcanic surroundings. The pH can fluctuate greatly because it is dependent on the amount of dissolved CO 2 in the water.The bank of Salmon Creek's headwaters was covered with alder trees, blackberry bushes, horsetails, grass, and soft mud. Lower Salmon Creek had alder trees and blackberry bushes hidden in the grass, and the bank was muddy. At the stream in Pumice Plane, the bank had thick moss, and there were white willows, lupines, and other plants along both sides of the bank. Cedar Creek's bank had large boulders, alder trees, ferns, and other plants that covered the water in shade. The bank needs to be in good condition, because if it's not, mud and other debris will wash into the creek and pollute it. At all the creeks I visited, I noticed that the banks had a diverse amount of plants. Previous analysis has shown that a diversity of plants along a creek's bank is essential.
An excellent creek bed is composed of gravel, pebbles, and sand so the female salmon can build her redd and lay her eggs; a good stream bed ensures returning salmon runs. The creek should have slow-moving water so the eggs don't float away, and shade from the surrounding trees and bushes. The headwaters of Salmon Creek, Cedar Creek, and the Pumice Plane all provide an excellent creekbed, but lower Salmon Creek has a muddy creekbed that is not suitable for salmon to lay their eggs in.
At the edge of Cedar Creek, boulders form pools which are home to black water skippers, periwinkles, and mayfly larvae.
From the information I collected, I was able to tell which creek was best suited for the needs of salmon and which creek was not able to supply the salmon with its needed habitat. I concluded that the headwaters of Salmon Creek are a good place for salmon to spawn because the low conductivity of the water indicates that it is not very polluted. The pH is within the standard spawning range, of 6.5 to 8.0, and the creekbed supplies gravel, pebbles, and sand for redds. The bank has a diversity of plants that provide shade.
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The lower part of Salmon Creek is the worst place for salmon to spawn because the conductivity is high (187 µsi). Also, lower Salmon Creek passes through farmlands, and livestock deposit feces into the creek, causing bacteria to grow. As salmon move upstream to the headwaters to spawn, they encounter the polluted area of Salmon Creek in Hazel Dell, which may prevent the fish from completing their trip to the headwaters.
Cedar Creek is another good place for fish to spawn because it also supplies the fish with their basic needs.There are many possible reasons for the lack of salmon runs in Salmon Creek. Some factors that I am aware of are: the foam I discovered; the pollutants in lower Salmon Creek from farmlands; and fertilizers, soaps, and other toxins in the water because of development.
I would like to further my research by exploring the entire length of Salmon Creek to determine whether the creek is being polluted, and the source of the pollution. I also would like to travel to other creeks near where I live and examine them to see if they are providing the basic requirements for salmon, and to ensure that my findings are not coincidental.
From doing this project, I have learned that each stream and creek is different. I learned that salmon need a certain environment to survive. I enjoyed traveling to parts of southwest Washington to compare streams and learn about the basic needs of salmon.
References
Alden, Peter, et al. National Audubon Society Field Guide to the Pacific Northwest. New York: Alfred A. Knopf, 1998.
Dyckman, Claire, Bill Way, and Pat Kelly. Clean Water, Streams and Fish. Seattle: Washington State Office of Environmental Education.
Goodson, Gar. Fishes of the Pacific Coast. Stanford, California: Stanford University Press, 1998.Little, Elbert L. National Audubon Society Field Guide to North American Trees. New York: Alfred A. Knopf, 1980.
Milne, Lorus and Margery Milne. National Audubon Society Field Guide to North American Insects. New York: Alfred A. Knopf, 1997.
Opler, Paul A. A Field Guide to Western Butterflies. New York: Houghton Mifflin, 1999.
Richard, Spellenberg. The Audubon Society Field Guide to North American Wildflowers. New York: Alfred A. Knopf, 1979.
Tarabochia, Kathy. Life Cycle of the Salmon. Seattle: Pacific Science Center, 1980."Water Quotes." Retrieved from the World Wide Web on December 28, 2002: www.inct.net/valleskey/water.html.