Trout in trouble
Fish surveys conducted last week in eight stretches of the Eagle River from Arrowhead to Gilman are showing a 30 percent or higher decline in the number of fish.
At this point, what happened is a mystery and more troubling is the fact that it reverses what had been a trend of improving fish numbers in the Eagle.
“I don’t think anybody has a great idea why,” said Bill Heicher, a retired 33-year veteran of the Colorado Division of Wildlife and fish counting volunteer for the last 15 years. “It’s looking like last year’s fish are basically not there.”
Fish biologist John Woodling suggested it might be a combination of factors including increased urban impacts from development along the banks of the river to natural events like last year’s high runoff -the second-highest- on record. Another possibility is the fish census this year was skewed by higher-than-normal runoff that made catching the fish more difficult, Woodling said. It’s the 15th year of counting the fish in the river.
Regardless, whatever is to blame, it has left some of the fish in bad condition.
“A lot of fish near Minturn were in wretched shape,” Woodling said. “They were skinny and thin.”
Woodling and others are going to review the data gathered during two days of capturing and measuring fish last week, then compare that to water quality data and to other data to see if the numbers present a reason for the steep decline in the numbers of fish.
Until this year, the revival of fish in the river below a seven-mile stretch killed by mine pollution in the mid-1980s had been a spectacular success.
The numbers of aquatic bugs, at first glance, appears to be the same as in previous years, Heicher said, but he said analysis of the data will validate that. That overall analysis of the fish and invertebrate data could, as it has in past years, take several months.
There was one malfunction involving the mine water treatment plant south of Minturn last year during which water with elevated zinc levels leaked into the river, but no fish kills were reported, said Caroline Bradford of the Eagle River Watershed Council, a local preservation group.
Up to this point the river cleanup has been a major success, but the river hasn’t completely healed and all the sources of pollution haven’t been shut off. There are still traces of dissolved zinc – toxic to fish – in the river at certain times of the year. That zinc has can harm the fish, according to scientists.
Woodling singled out a tagged brown trout near Minturn that has been repeatedly caught and released to illustrate what’s going on in the restored stretch of the Eagle River.
Trout P-67 has lived in the Eagle River near Minturn for the past seven years and is living proof of the success of the cleanup of the river. It’s also proof that things aren’t completely restored.
P-67 is just over 10 inches long – underweight and small for a 7-year-old fish – but it appears healthy. It hatched from an egg in 1997, about a decade after untreated tailings from the mine killed virtually all aquatic life in a seven mile stretch of river between the mine and Dowd Junction. P-67 has been caught, measured and weighed four years in a row.
The trout and thousands like him have re-populated the restored stretches of the Eagle River in increasing numbers. Today there’s approximately 200 pounds of fish per surface acre in the river (an area about the size of a football field), according to wildlife experts who tally fish numbers. That’s nearly the same as stretches of the river that were not affected by the mine.
But P67 also illustrates perfectly the remaining challenges for the Eagle River. He’s shorter and weighs less than similar-aged fish found in stretches of the river that weren’t destroyed by the mine’s pollution. Zinc, according to wildlife officials, is the culprit.
In the 17 years since millions of gallons of contaminated water from the Eagle Mine spilled into the river, the subsequent cleanup of the river is one of only two successful restoration projects across the country, Woodling said. The other is Idaho’s Clark’s Fork.
The Eagle River is close to being cleaned up – how close is subjective – but it still contains slightly elevated levels of zinc from the mine,. Zinc, is stunting the growth of the fish in the restored part of the river because it creates what Woodling calls, “a physiological cost.”
Fish can become tolerant of elevated zinc – levels of 250 parts or more per billion – but they don’t grow as fast as fish who aren’t exposed to zinc. That’s the approximate zinc concentration in the river during low flow months in the early spring when it’s at it highest. But it’s still a far cleaner river than it was when the mine’s pollution colored the river orange.
“It’s a lot different than 1990,” said Woodling. In 1990, Viacom, the mine owner, under pressure from state and federal governments, began a $70 million cleanup of metals-contaminated tailings and mine water.
“Now there are fishermen. That’s a far cry from what was going on in 1990,” Woodling said.
Late last month, Woodling presented a “state of the fish” address to the attendees of the Eagle River Watershed Council’s monthly Waterwise Wednesday meeting that outlined the success of the restoration. It preceded the new data showing the decline of fish in the river that was collected Thursday and Friday.
“The Eagle River still gets an ‘A’,” Woodling said. But he called the growth level of the fish in the restored stretch of the river “pathetic.” Part of the reason is the environment of the river – it’s cold and has a short “growing season” for fish, Woodling said.
Fish are an indicator species that function like the canary miners brought into coal mines to warn them of poisonous gasses.
The Eagle Mine Superfund cleanup was a compromise forged not in a laboratory, but in court by lawyers and environmental experts, from Viacom, the U.S. Environmental Protection Agency, the Colorado Attorney General’s Office and the state Department of Public Health and Environment. They settled on using the hardier brown trout as a a key indicator species that could be used to judge the recovery of the river and its ability to sustain a diversified biological community.
The rainbow trout and cutthroat trout are not as tolerant of polluted water, Woodling said.
It was decided the river cleanup would be a success when the restored sites had a fish population that was 85 percent of the stretches of the river that were not hurt by the mine’s pollution. The numbers in some of the restored sections actually exceeded that during a couple of years, but this year that trend has been stunningly reversed.
Much of the zinc that may be causing the problem is coming from one small drainage south of Minturn – Bishop Gulch. But Viacom no longer is saddled with the responsibility of more river cleanup.
“They’re done,” Woodling said. The active cleanup phase of the project ended in October 2002. Viacom, however, continues to operate a mine water treatment plant that removes the metals from the mine water before returning it to the stream.
“Over the last three years the level of zinc in the river is not decreasing,” Woodling said. “That’s something the community needs to be aware of. You’re not going to get decreases without more restoration.”
The zinc levels spike in March and April when snow melts and carries the mineral into the stream, according to project managers. The mine now has less of an impact on the river than do natural events such as drought and floods, Woodling said. Together, natural forces and zinc may be reducing the numbers of fish.
Wendy Naugle, of the state health department, said during the state of the river meeting that new, tighter regulation of the level of metals allowed in the river are needed, but state and federal agencies can’t agree on what the appropriate levels are. Her department has settled on 106 parts per billion of zinc while the Colorado Division of Wildlife suggests 225 and the EPA, yet another number.
One of the parts of the aquatic food chain, the sculpin minnow – a food source for trout – is virtually nonexistent in the restored stretch of the river, Woodling said. That’s because it has little tolerance to zinc. “We need better (metal) standards,” he said.
The state has been measuring the water quality against the fish and aquatic bugs in the river, Naugle said. Those complex measurements require scientists to evaluate how water quality has affected the creatures which live in the river. It’s a difficult evaluation because the water quality measurements precede the once-a-year biological measurements and are difficult to correlate, she said.
The final survey of the fish and aquatic bugs in the river was completed Friday. What happens now in the river is up to the people who live in Eagle County, Woodling said. Cleaning up the remaining metals in the river is going to take lots of time, effort and money just to achieve minuscule improvements, he said.
It’s not clear who would be financially responsible if the mine or the tailings are proven to be the source of the problem. Viacom’s portion of the cleanup has been completed, according to cleanup officials, and it’s no longer responsible.
“We’ve only got a piece of the information,” said Gary Baughman, director of the hazardous materials and waste management division of the Colorado Department of Public Health and Environment. “We’ve got to get the rest of the information before we reach any conclusions.
Anecdotal evidence seems to contradict some of the science. Bill Perry of Avon-based Flyfishing Outfitters said he fished the Eagle last weekend from Edwards through Wolcott and caught lots of large fish.
Cliff Thompson can be reached via e-mail at: firstname.lastname@example.org or by calling 949-0555 ext. 450.