Jeff Adams steps gingerly into a riffle of fast-moving, clear water in Bear Creek, and, while 17 people watch, performs the bug dance.

With the thick rubber heel of his green, thigh-high boots, Adams churns up a small brown cloud of sediment, which is carried by the current a few feet downstream to a collecting net. Hiding in the sediment and clinging to smooth river rocks are caddis fly, mayfly and crane fly larvae, snails and worms. These tiny, sensitive stream residents can speak volumes about the health of their home.

Known in scientific circles as benthic macroinvertebrates, the aquatic animals collected in the back of Adams' net are some of the first to be affected by changes in stream health. Some can only exist in a narrow range of temperatures, so when a stream gets too warm, they disappear. Others react to pollutants in the water. Submitted photo

Snails live on land and in fresh and salt water. Each is about the size of a grain of sand. Aquatic animals are the first to be affected by changes to stream environments.Submitted photo

Caddis fly larvae such as these can tell water quality experts about the health of streams and watersheds.Submitted photo

A flatheaded mayfly clings tightly to rocks as it scrapes microscopic plants off the rocks for food.

"Mayflies hate heavy metals," Adams said.

The study of these macroinvertebrates is called biological monitoring - biomonitoring for short. When added to chemical and physical data traditionally gathered by water quality experts, a more holistic picture of stream health emerges.

Adams, an aquatic biologist with the Portland-based Xerces Society, brought 17 educators, watershed specialists and state agency workers, to Bear Creek - just downstream from Astoria's city reservoir - to introduce them to biomonitoring.

Named for the first butterfly known to become extinct, in part because of human habitat destruction, the Xerces Society concerns itself with invertebrate conservation, endangered insect species and threats to pollinators.

BENJAMIN ROMANO - The Daily Astorian

Jeff Adams, leader of a one-day workshop on water quality monitoring techniques, pulls tiny snails, worms and bug larvae off of a rock from Bear Creek. The health of these sensitive critters can tell scientists about the health of the creek.The free, introductory workshop Tuesday - one of 10 around the Northwest Adams will lead this summer - drew water quality specialists from groups like Ecola Creek Awareness Project, Youngs River Watershed Council, Butterflies Forever, Oregon Department of Fish and Wildlife and The Nature Conservancy.

"Obviously this is an evolving science," said Jim Scheller, as he stood on the rocky bank of Bear Creek. "It's just fascinating."

Scheller, representing the Skipanon Watershed Council, said his organization has been measuring dissolved oxygen, temperature, salinity and taking fish surveys in and around the Skipanon River, but added: "We need to complement this with biological monitoring."

The Oregon Department of Environmental Quality is using biomonitoring techniques to check stream health. Between 250 and 300 sites in the Coast Range have been sampled, including many in Clatsop County, said Rick Hafele, DEQ's biomonitoring section manager.

Submitted photo

This mayfly nymph is a scraper; it uses a comb of spines on its mouthparts to feed on microscopic algae. This nymph is usually found in small, rapidly flowing streams among pebbles, near banks, and among vegetation and organic debris.A part of Gov. John Kitzhaber's Oregon Plan for salmon and watersheds, DEQ's biomonitoring program is designed to gather information across a large geographical area on the chemical and physical status of the streams and the biological communities, Hafele said.

"Water quality standards are set to be at levels that not only protect human health but also the aquatic life in the streams," he said. "The only way to understand if the biological community is being protected is to go out and measure it."

That's exactly what participants in Adams' workshops learn to do.

Before Adams performed the bug dance, participants measured a four-square-foot sampling area in the stream. He held the net at the downstream edge of a patch of gurgling water and participants began scrubbing smooth river stones with their hands, washing the minuscule bug larvae into the net.

Adams emptied the net into a white plastic tub so everyone could take a closer look at the catch. At first, it looked like nothing more than sediment, tiny rocks and sticks sloshing back and forth. But closer inspection revealed a huge array of life.

"If you do it by eye, you're going to miss a lot of stuff," he said, as participants began straining out individual larvae with square pieces of mesh and categorizing them in ice cube trays. "A lot of these things look like sand."

The workshop was meant to introduce participants to biomonitoring techniques. If this had been an actual study, collected materials would have been examined under a microscope or sent to a lab to be categorized.

Adams predicted they would find about 40 species in the small stream area they surveyed. He guessed that upwards of 2,000 individual macroinvertebrates live in that area, or roughly 500 per square foot.

So how healthy is Bear Creek?

"In a good, healthy Northwest coastal stream, you should have about eight to 10 mayflies and eight to 10 caddis flies in about eight square feet of water," Adams said.

Looking in only four square feet of water, the group found at least three different caddis flies and four stoneflies, which are fairly sensitive and the most likely to disappear when water quality is poor.

"That's a pretty good sign," Adams said. "You get into an urban stream ... you get none."