Tag Archives: fisheries

Characterizing off-channel habitats in the Willamette River: Fish need to cool off too!

During the summer, when the mercury clears triple digits on the Fahrenheit scale, people seek out cooler spaces. Shaded parks, air conditioned ice cream parlors, and community pools are often top places to beat the heat. If you’re a resident of Corvallis, Oregon, you may head downtown to dip your toes in the Willamette River. Yet while the river offers a break from the hot temperatures for us, it is much too warm for the cold water fishes that call it home.

Where do fish go to cool off?

As a master’s student in the Water Resources Graduate Program at Oregon State University, Carolyn Gombert is working to understand where cold water habitat is located along the Willamette River. More importantly, she is seeking to understand the riverine and geomorphic processes responsible for creating the fishes’ version of our air conditioned ice cream parlors. By placing waterproof temperature loggers along sites in the upper Willamette, she hopes to shed light both on the temporal and spatial distribution of cold water patches, as well as the creation mechanisms behind such habitats.

 

The cart before the horse: seeking to reconcile science and policy

Because the Willamette Basin is home to Cutthroat trout and Chinook salmon, the river is subject to the temperature standard adopted by the state of Oregon in 2003. Between May through October, Cutthroat and Chinook require water cooler than 18 degrees Celsius (64.4 degrees Fahrenheit). Currently, the main channel of the Willamette regularly exceeds this threshold. The coolest water during this time is found in side channels or alcoves off the main stem. While Oregon law recognizes the benefits these “cold water refuges” can provide, our scientific understanding of how these features change over time is still in its early stages.

Emerging stories

Data collection for Carolyn’s project is slated to wrap up during September of 2017. However, preliminary results from temperature monitoring efforts suggest the subsurface flow of river water through gravel and sediment plays a critical role in determining water temperature. By pairing results from summer field work with historical data such as air photos and laser-based mapping techniques (LiDAR) like in the image below, it will be possible to link geomorphic change on the Willamette to its current temperature distributions.

Between 1994 and 2000, the Willamette River near Harrisburg, Oregon shifted from a path along the left bank to one along the right bank. This avulsion would have happened during a high flow event, likely the 1996 flood.

No stranger to narratives

Prior to beginning her work in hydrology at OSU, Carolyn earned a bachelor’s in English and taught reading at the middle school level. Her undergraduate work in creative writing neither taught her how to convert temperature units from Fahrenheit to Celsius nor how to maneuver in a canoe. But the time she spent crafting stories did show her that characters are not to be forced into a plot, much like data is not to be forced into a pre-meditated conclusion. Being fortunate enough to work with Stephen Lancaster as a primary advisor, Carolyn looks forward to exploring the subtleties that surface from the summer’s data.

If you’d like to hear more about the results from Carolyn’s work, she will be at the OSU Hydrophiles’ Pacific Northwest Water Research Symposium, April 23-24, 2018. Feel free to check out past Symposiums here. Additionally, to hear more about Carolyn’s journey through graduate school, you can listen to her interview on the Happie Heads podcast.

Carolyn conducting field work on the Willamette.

Carolyn Gombert wrote the bulk of this post, with a few edits contributed by ID hosts.

Learn the past. Speak the present. Guide the future.

Lake Victoria, sitting just below the equator in eastern Africa, shared between the countries of Kenya, Uganda, and Tanzania is the second largest freshwater lake in the world. To put that into

Early 20th century map of Lake Victoria

Colonial territories surrounding Lake Victoria in the early 20th Century

perspective, at 68,800 square kilometers, Lake Victoria is larger than the country of Switzerland (41,285 sq. km.). Beyond its immense size and grandeur, it is also one of the most important sites on earth for our current understanding of evolution because of one rapidly-diversifying group of fishes: the cichlids, which include both tilapia, an important food source, and aquarium fish such as angelfish.

 

The cichlids in Lake Victoria are especially interesting because that body of water dried out and refilled less than 15,000 years ago. This may seem like a long time, but on a geologic and evolutionary timescale, that’s less than the blink of an eye. Consider that before 1980, itwas estimated that there were over 500 species of cichlids in Lake Victoria. To contrast that with our own timeframe, the speciation time from our last common ancestor with chimps was on the order of millions of years ago. The fish in this lake are evolving at record speeds.

Traditionally haplochromines were harvested and dried as a food source for indigenous peoples Most of these practices were outlawed in 1908 Most subsistence fishing on Lake Victoria today is illegal

Traditionally haplochromines were harvested and dried as a food source for indigenous peoples Most of these practices were outlawed in 1908 Most subsistence fishing on Lake Victoria today is illegal

Today, the populations of cichlids in Lake Victoria have plummeted and many species are either endangered or extinct. The extinction was due to environmental pressures and invasive species such as the nile perch, a large predator game fish with an appetite for a group of small cichlid fish known as Haplochromis. Like many invasive species, the introduction of the nile perch was no accident. It was introduced to stem the overfishing of tilapia in the 1920s. This worked, but at the price of hundreds of species of Haplochromis. Now that the biodiversity in the lake is reduced, there are efforts to protect these species that are informed by scientific inquiry, but who gets a say in how management decisions are made? How did the focus of inquisition change over the past hundred years?

 

Cat. Man. Do.

Matt his cat work on writing Matt’s thesis

Our guest, Matt McConnell, is trying to answer these questions and trying to understand how communication between scientists and non-scientists affect how science is done. As a Masters Student in the History of Science department or Oregon State University, he is digging through the archives, trying to understand the changing scientific values surrounding Lake Victoria in the 20th century. Is the lake important as a resource or as a haven for species? Why should we care? Our current notion of science is that it is objective, but as we look into its history, science is value-driven, which is culturally laden; the question is, who’s culture is asking the questions and who’s culture is affected? In our current time, we are hearing about resource management and those are informed by scientific inquiry. Science is the answer, but it affects farmers and fishermen and their opinions are often denigrated in favor of science. Science is considered an objective measure, but it is really a cultural decision. Practitioners of science not only need to communicate their values, but they need to listen.

Matt and the 2016 History of Science cohort enjoy a day in the sun in Seattle at an Environmental Humanities Conference

Matt and the 2016 History of Science cohort enjoy a day in the sun in Seattle at an Environmental Humanities Conference

Tune in Sunday, July 3rd at 7PM PDT on 88.7FM or live stream to hear Matt talk about his journey with the history of science and science communication.