Studying the health of Suttle Lake

A monitoring buoy in Suttle Lake has gathered its first partial season of data on lake conditions.

Volunteers recently removed the NexSens CB-450 data buoy from the water to store it for the winter. It will go back into the lake once winter conditions slide into spring, so that key data can be collected to help shape how the Forest Service manages the lake toward reintroduction of sockeye salmon.

The buoy is equipped with a number of sensors to gather measurements on conditions affecting the lake's food web and salmon stocks. According to Dan Kelly of Environmental Monitor, these include a Lufft WS501 weather sensor; Hydrolab DS5 sonde and two LI-COR sensors tracking photosynthetically active radiation (PAR). The weather sensor logs data on air temperature, humidity, barometric pressure, wind and global solar radiation. The sonde is outfitted to track temperature, conductivity, pH, dissolved oxygen and pigments. An LI-190R measures PAR above water, while an LI-192 tracks it below the surface to a depth of five feet.

All of the sensors are powered by three 10-watt solar panels and send measurements to a NexSens data logger housed within the buoy. The logger is equipped with cellular telemetry to broadcast real-time measurements to managers at the High Lakes Aquatic Alliance Foundation.

An impetus behind the project is a noted decline in the size of kokanee caught in the lake.

In 2003 the kokanee -a land-locked cousin of the sockeye -measured about 18 inches as adults, but in 2016 adults were found to be only five to six inches long. The buoy will help provide vital information as to why this is happening, and (hopefully) help correct it.

Frank Conte, a retired USO limnology professor is the founder of the organization. Conte and HLAAF members and partners put a great deal of effort, money, engineering and dedication into creating the monitoring buoy.

Dave Huni has been volunteering as a technical consultant for the project. He told The Nugget that the measurements taken by the buoy can, "tell you what kind of runoff (is going) into the lake" and provide information on algae growth and food sources for fish.

Volunteers will also trawl for fish and "look at real-life measurements in the fish and the algae and compare that with what the data is."

The buoy didn't go into the lake until July 7 this year, and the volunteers took it out at the end of September. Huni said that the group wants to get the buoy in the lake for a "full growing season" next year - April through September. The monitoring may go on for several years.

"Three years would give us a good picture on what different things are going on, one way or another," Huni said.

Efforts to save sockeye salmon got into high gear around 2012 with the removal of dams and other objects that were blocking sockeye from reaching Suttle Lake, like the culverts that were under Road 12. Forest Service fishery biologist Nate Dachtler and his crew modified several of the obstructions and other features that prevented salmon from reaching the lake.

Sockeye salmon, aka red salmon, or blueback salmon, is an anadromous fish found in the northern Pacific Ocean and rivers such as the Columbia. Native peoples and the European-American pioneers depended on them for food.

They can grow to three feet in length and must spawn in freshwater lakes, streams and rivers where they remain until they are ready to migrate to the ocean. Sockeye use patterns of well-lit, open surface waters in the lake, away from the shore. This is the main photosynthetic body of the lake. Because sockeye can change their position in the water column, also adjusting timing and length of feeding and choice of prey to minimize the likelihood of predation, it is vital to understand these factors -which the HLAAF monitoring buoy helps to do.

Sockeye, unlike other species of Pacific salmon, feed extensively on zooplankton, organisms drifting in the lake. Individual zooplankton are usually microscopic, but some, such as copepods and aquatic insect larvae, as well as flying adult insects and shrimp, are larger and visible to the naked eye.

Upon reaching their home waters, the fish must have the conditions that will not only provide habitat for spawning, but the biological qualities that will keep the fry and fingerlings going and provide the necessary biological and physical attributes to get them past all they have to confront to reach the ocean.

The team of people and organizations to make all that happen is varied and dedicated. The Confederated Tribes of Warm Springs, PGE, USFS, Oregon Department of Fish & Wildlife, and HLAAF volunteers and members work together to help create the conditions that will provide safe passage for the sockeye, both ways - and at the same time help the sockeye's cousins, kokanee, to survive in Suttle Lake.

The buoy is currently in storage, stripped of its sensors. Volunteers will maintain its battery through the winter before gearing it up again for a full season in the lake.

Editor's note: Nugget reporter Jim Anderson contributed to this story.

Author Bio

Jim Cornelius, Editor in Chief

Jim Cornelius is editor in chief of The Nugget and author of “Warriors of the Wildlands: True Tales of the Frontier Partisans.” A history buff, he explores frontier history across three centuries and several continents on his podcast, The Frontier Partisans. For more information visit www.frontierpartisans.com.

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