This bald eagle — one of many — watched from a tree for a passing smelt in the Grays River.

GRAYS RIVER — The annual spawning of eulachon (Thaleicthys pacificus), commonly known as the Pacific smelt, has been occurring in Grays River for more than a week.

One of several species of smelts (Osmeridae), eulachon were once called “candle fish” and “oil fish.” Due to their natural oiliness, a dried smelt with a wick stuck in its mouth can be burned like a candle.

These small fish used to be a staple for Native Americans and, during the first half of the last century, millions of pounds of Pacific smelt were commercially harvested on an annual basis.

The male smelt are the first to appear in Northwest rivers, soon thereafter followed by the females. A single tiny female can produce some 40,000 eggs that, when fertilized by the males, attach themselves to the sand and debris on the river bottoms. When hatched, five to six weeks later, the larval smelt are quickly washed downstream by river currents and out to sea. They remain in the ocean environment for three to five years before migrating to coastal rivers to spawn.

Smelt spawning attracts large numbers of predatory birds such as bald eagles and gulls. On Saturday, March 13, more than 25 eagles were observed perched on riverside trees and flying above just a quarter mile stretch of Grays River paralleling the Altoona-Pillar Rock road near Devil’s Elbow. By the next day, the presence of eagles and thousands of gulls indicated the smelt concentration had moved upstream above the Rosburg Hall.

Smelt runs diminished to the point where eulachons were placed on the Endangered Species List in 2010, after their population hit all-time lows starting in the 1990s and collapsed in 2005. Smelt abundance increased steadily from 2011 to 2014, reaching an estimated recent peak abundance of 16.6 million pounds in 2014, followed by a sharp decline to 370,000 pounds in 2018. The 2019 return improved to an estimated 4.2 million pounds.

Due to sampling constraints imposed by covid-19, the current run-size could not be determined directly from larval sampling but is estimated to be similar to the 2019 return at approximately 3.8 million pounds, according to the Oregon Department of Fish and Wildlife. This was enough to warrant a modest commercial gillnet fishery on the Columbia’s main stem in February, partly in order to be able to monitor how the smelt population is doing.

No recreation harvest is allowed at this time.