Scientists check Fryingpan River health
October 31, 2013
Bill Miller and Chad Rudow dug down into the muck of the Fryingpan River on Monday to learn if concerns about the famed trout stream's health are warranted.
They used a contraption called a sampler to fill three small containers with a collection of sediment, algae, twigs and, mostly importantly, bugs from the river bottom. Miller, a consultant hired by the Basalt-based Roaring Fork Conservancy, will analyze the mixture back in his laboratory and then repeat the process next spring.
Miller and Rudow, water quality coordinator for the conservancy, worked with volunteer Grace Seigle to collect three samples of bugs from three sites on the river — one near the dam about 13 miles east of Basalt, one about halfway down the river near the confluence with Taylor Creek and one near town. They also are placing two temperature loggers at each of the three sites.
"These little guys can run months at a time without any help," Rudow said, handling the quarter-sized specialty thermometers. They were placed in protective PVC containers with numerous holes for the water to rush through. They were anchored to the stream bottom with galvanized wire and set to record the temperatures every hour. Data will be downloaded periodically from now until April, when the second bug collection will take place, again with three samples from three sites.
A couple of miles downstream from Rudow and Miller, 10 workers from Colorado Parks and Wildlife marched up the river in a steady line. Most of them held a probe in one hand and a net with a large handle in the other. The probes give a small electrical shock that makes the muscles of the fish contract, according to Kendall Bakish, aquatic biologist with the agency. The fish are attracted toward the electrical impulse and are netted by the workers. They regularly capture trout of varying sizes as they make their way upstream. They place the fish in netted "cars" bobbing in the water that other workers pull behind them.
The wildlife division workers made two passes in a section of the lower Fryingpan River about three miles east of Basalt. Two other passes in different stretches of the river, where fish are more abundant, are planned in coming days.
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The wildlife division's fish count is a routine procedure that's been carried out regularly since 1979, Bakish said. The agency measures, weighs and notes the type of trout found in the surveys. The fish are released unharmed. Bakish said her preliminary observation is that the fish numbers and sizes are consistent with what she has seen in past surveys.
Data have been collected since 1979, when the lower Fryingpan River was first designated as a Gold Medal trout stream. That means it has at least 60 pounds of trout per acre and more than 12 trout greater than 14 inches per acre.
About 14 miles of the Fryingpan River and 28 miles of the Roaring Fork River meet the criteria.
Concerns arose this summer about the Fryingpan River habitat when several anglers and riverside residents familiar with the environment reported seeing lower fish numbers, including fewer large trout, according to a report on the Roaring Fork Conservancy's website.
Observers also reported fewer macroinvertebrates, the bugs that are vital food for the fish. Some observers noticed hatches only in isolated pockets.
Colorado Parks and Wildlife already had the fish count scheduled for Monday as part of its routine operations. The nonprofit Roaring Fork Conservancy raised $35,000 to hire Miller to sample for bugs in the fall and spring, to monitor temperatures throughout the winter, and to undertake other studies.
Miller Ecological Consultants also will study the extent of Didymosphenia geminata, algae that also is known as "rock snot" because it covers rocks.
Miller's work and the fish count dovetail nicely.
"It just makes it a more complete biological picture," said Sarah Johnson, education and outreach coordinator for the Roaring Fork Conservancy.
Miller performed the same work, at the same sites, in 2002 and 2003, so he will have numbers to compare when the analysis begins next spring.
"We are putting the science to the test," said Rick Lofaro, the conservancy's executive director. The science will determine whether the anecdotal evidence is accurate, he said.
Determining how many macroinvertebrates are present in the ecosystem is a key to determining whether the fish population can be supported.
"They are the canaries in the coal mine," Lofaro said of the bugs.
Drought conditions last winter created low flows on the lower Fryingpan and elevated concerns about the effect on the ecosystem. The Roaring Fork Conservancy's website shows that the flow below the dam was about 40 cubic feet per second for about four months, starting in late November.
The U.S. Bureau of Reclamation kept more water in the reservoir and released less than normal during winters to try to make sure the reservoir filled during spring runoff. It succeeded. Lofaro said the Reclamation Bureau's early estimate is that it will be able to maintain flows more around 90 cubic feet per second this winter. That could be vital, he said, to avoid the buildup of anchor ice. When flows are low and temperatures are low for a sustained time, ice builds from the stream bottom. It eventually breaks free and scours the bottom, potentially killing bugs vital to the food chain.
Results of Miller's study won't be available until all data are collected next spring and then analyzed.