The three of us also managed to stop at a hatchery or two. The most interesting hatchery was the Poudre River Rearing Unit, established in 1948, located a long drive up the Cache la Poudre canyon on roads that would later be devastated by floods and mudflows brought by heavy September rains. Although the hatchery is capable of producing 350,000 trout per year, it is not operating at full capacity. In fact, the production is only approximately 50,000 catchable trout per year, one-seventh of its capacity. It is a shell of its former self largely because the interplay between three exotic invasive species brought to the area. The first species was rainbow trout, which were intentionally introduced to the state by hatcheries, including the Poudre unit, as part of the State’s grand plan to improve fishing opportunities. The state also stocked brown trout from Europe as part of this same long-term initiative. Unfortunately, unbeknownst to state biologists, this second non-native species brought its own exotic friends along in the form of Myxobolus cerebralis, the parasite responsible for whirling disease.
Brown trout evolved with this parasitic creature and had developed some resistance to this unwanted jockey. However, Myxobolus cerebralis was new to rainbow trout. Because rainbow trout had no natural immunity to the new parasite, the impact was devastating. Hatcheries soon became breeding grounds for both trout and whirling disease. Fish stocked from these ponds would inevitably contaminate the majority of miles of trout habitat in the state. Eventually the cause for whirling disease was discovered and portions of hatcheries were closed. In particular, many of the earthen rearing ponds, including the ones in Colorado were emptied and left dry. The State determined that is was almost impossible to rid the earth-lined ponds of the parasites. Concrete runs, which were easier to disinfect soon became the focal point for trout rearing.
Although whirling disease did and does cause devastation to all the native subspecies of cutthroat trout in the state, it also provided a bit of an opportunity to rethink the wisdom of stocking rainbow trout, which interbreed with native cutthroat trout and create many problems as a result. Whirling disease was essentially helping to wipe out many rainbow trout, which at least helped address some of the problems cutthroat trout faced. However, the state did not really want to lose the highly-profitable rainbow trout from its waters, and instead sought out resistant strains of rainbow trout. The state now proudly advertises a new strain of fish, Hofer rainbow trout, with a higher resistance to whirling disease. The new rainbow strain originated from the Columbia River watershed, but came to Colorado by way of Germany. Hofers developed their resistance in Germany because they have evolved for several generations in hatchery systems and streams contaminated with whirling disease. The state is happy to report that Hofers are fast growing fish, largely because of their long history of domestication. This leads to aggressive feeding behavior and reduced hiding behaviors that might doom them as wild fish, but are fine for the instant put-and-take fisheries the state is trying to maintain. What all this will mean for the poor cutthroat trout is hard to say at this point.
At the Poudre River Rearing Unit, a whole line of abandoned rearing ponds exist along the southern outskirts of the hatchery property between two long concrete runs and the modern river. From the air it must resemble a bit of a rotten rind along the outer edge of the hatchery. These artificial artifacts are monuments to the problems associated with the stocking of exotic invasive trout and the whirling disease they helped spread. They remain empty because of the problem disease that was introduced can never be erased. However, it appears that some time in the future, they will again be put back into operation and filled with Hofers to feed angler’s never ending hunger for big fish.
Although these ponds were visible from the road, they were not the first thing that caught our attention as we pulled into the parking lot. Instead, when we first pulled in we noticed a large educational sign labeled “From Egg to Creel.” The sign explained the lifecycle of trout with a six sequence display. The last panel ended with a little angling propaganda: “it is small wonder that the wily trout manage to avoid all but the most skillful anglers.”
As we walked towards the hatchery runs, we passed a pellet dispenser that looked like an old gumball machine. I certainly remember begging my parents for dimes and nickels whenever we passed gumball machines in my youth, so I was not surprised when my daughter asked for a quarter to buy some pellets to feed the trout. Although a quarter was certainly not out of my budget range, I didn’t particularly like the idea of supporting the operation of the hatchery at any funding level. Displaying true New England frugality, my daughter and I quickly determined that it was possible to get a handful of pellets by just jiggling the handle of the dispenser. We nervously watched over our shoulders as we pilfered pellets from the apparatus.
With pellets in hand we walked over to two long runs that were partially covered with white fabric stretched across an arched frame. Even before we tossed in the first pellets, the trout seemed happy to see us. We soon discovered that the Poudre River Hatchery relied on demand feeders as its primary method for feeding, not quarter-wielding visitors. The demand feeders were fiberglass cylinders slightly larger in size than five-gallon buckets. The bottom of the feeders was funnel shaped with a small opening at the base. A metal rod hung out of the hole and down into the water. It took a while to see the end of the rod in the water because trout were swimming below the feeder in a frenzied circle. When I finally did notice the end of the metal rod, I saw it had a small red plastic target on it that was, interestingly enough, hook shaped. When fish hit the rod with enough force, it would shake a few pellets loose from the fiberglass hopper and the swirling swarm of fish would twist and turn to feed. The whole system did not look much like anything you would see in nature, but I figured at least the trout were getting some exercise.
We made sure to grab a few pictures of the demand feeder circus as we walked along the pen. At the upstream end of the run we saw the water supply, which appeared to be drawn off of the main river. We then walked back down the far side of the concrete channel to see where the discharge water was going. Although the outflow appeared to originally dump into a downstream rearing pond, the flow was now funneled into two large PVC pipes that ran along the bed of the dry pond. The pipes then poked through the earthen dam of the far side and discharged into a small channel on the downstream end of the hatchery.
As we peered down a few feet from the northern edge of the canal, we saw the effluent water from the hatchery exit the pipes and flow through a small sheet metal structure called a Parshall flume. A Parshall flume is used by hydrologists to create a stable water surface elevation, called the stage, for a given discharge. The State surely installed the flume to accurately determine the volume of water leaving the hatchery. Unfortunately, the flume does nothing to improve water quality. Curious to see if anything was done to treat water before it was released to the Cache la Poudre River, we continued downstream along the path shadowing the little effluent canal.
We pushed ourselves through a few sparse willows and immediately came face to face with a small entourage of anglers. A family had carefully positioned themselves to fish what they thought would be the most productive section of water in the area. Three male anglers stood on a small bar with their backs to the Cache la Poudre River and the distant backdrop of the Rocky Mountains. Instead, they faced the little cove created by the confluence of the hatchery discharge channel and the river. Perhaps these were the skillful anglers the hatchery sign had talked about. They sought the trout wily enough to feed on the waste emanating from the hatchery. Several other party members stood on the shore cheering on the family fishing derby. Short casts were directed to the area where nutrient-rich and medicine-contaminated water from the hatchery first made contact with the more pure river.
The entire scene was a bit surreal and entirely emblematic of what trout fishing has become. These anglers had turned their backs on natural river systems to focus on products spit out from hatcheries to supply their entertainment. Stream pollution, biologic invaders that become ecosystem disruptors and manipulated landscapes with artificial channels were all carefully overlooked as they worked to end the day’s adventure with a big trout on the end of a hook.