How to Catch Stocked Trout

Stream just stocked, and you were skunked again? Blamed it on the "locals?" Or is something more sinister at work? A gang of rowdy blue herons? Need help figuring out how to catch stocked trout fly fishing?

You probably have the same questions as most – here they are, and this article answers them!

• Where to catch trout?
• What to use to catch trout?
• Where is the best place to catch trout?
• Why are trout so hard to catch?
• When to catch trout?

Frustrating! You have a fly box stuffed to the gills with every likely pattern reflecting every growth stage. You know the hatch, and you see the stocking schedule. You know you can catch fish! So, why DO you get skunked? Maybe the question is not "how" but "where." The simple truth is that anglers catch 90% of fish in 10% of the water. Any technique will work once you identify that ideal location!

Stockers have been driving fisheries professionals insane for years, with their central questions being the same as ours, "What happened to all the fish? Were they caught? Did they die? Did they leave?" Understanding the answers is crucial to their mission to provide an excellent angling experience that, in turn, stimulates license sales supporting hatchery programs. A Wyoming Fish and Game presentation succinctly stated the problem regarding tailwater trout survival: "How do you lose 250,000 trout?" Many experts have puzzled through the issue. Thankfully, they produced studies focused on answering these compelling questions that, if understood and lessons applied, will improve your day on the stream. The studies all reach the same general set of conclusions; an academic event as rare as your teenager offering to take out the garbage.

You may think a stream is cleaned out, but you're mistaken unless fishing with hand grenades is legal! A comprehensive British study discovered anglers caught only 40% of the stockers planted, and of that 40%, anglers caught 65% within five weeks of the stocking. Even when you factor the 40% number upwards for poaching and the heron gang, there is plenty of trout cruising the stream after the localized slaughter following the publication of the daily stocking report. So, why do you get skunked if there are so many uncaught fish?

When taken off a diet of fish pellets, a freshly stocked trout takes time to learn what to eat. Understanding the timeline is critical – especially for fly fishermen who rely on fooling trout with replicas of natural food. Brown trout present the worst-case scenario taking up to 50 days to adapt to natural foods completely. The good news is rainbow trout, a hatchery favorite, begin their slow adaptation to a wild diet in about a week. But, even their learning curve can still be slow. The Oklahoma Department of Wildlife Conservation confirmed this in April 2005 when they examined the stomach contents of rainbow trout stocked in January. In Oklahoma study-speak, "Non-food items were the dominant prey item." However, non-food items comprised a significantly smaller portion of the fish's intake by June, dropping from 27% in April to 11%. While the actual food items in the Oklahoma trout diet were primarily snails and invertebrates, you should not extrapolate that mix directly to local water since your environment is probably different.

All this implies the advantage slowly tips in favor of the angler. If you put your faith in the fact that 60% of stocked trout were unaccounted for, you can afford to wait for the fish to adapt to the wild. The longer a stocker is a resident in a stream, the more it will learn how to feed. In particular, fly fishermen should see trout interest in dry flies and nymphs pick up in direct proportion to time in the water as they adapt and learn through trial and error. Conversely, if you remain convinced you must hit the stream soon after stocking to catch anything, you should focus on bright streamers to provoke reaction strikes. Another option some fly anglers use (mostly jokingly) is a fly that looks like a food pellet rather than using traditional dries or nymphs. The transition to natural food is not the end of the story. By waiting for a stocker to develop a taste for stream fare, you give them time to disappear. Where do they go?

Finding the answer is precisely what motivated the Pennsylvania Fish and Boat Commission to conduct a series of studies between 2003 and 2006 in reaction to complaints from anglers asserting the fish were gone by opening day. It turns out the anglers were right. The Pennsylvania studies concluded that rainbow trout would remain where they were stocked for three days, browns for seven, and brookies for ten.

Once the trout adapt, they move. They move downstream. Some even take giant steps. The Pennsylvania study reports it found one radio-tagged rainbow a staggering 123 miles from its stocking location. The most adventurous brown moved six miles, and the comparable brookie, 7.5 miles. Although the study was silent on how far a stocker typically runs since it limited recapture efforts to an arbitrary 300 yards, a South Dakota study of Rapid Creek pegged the average distance at 224 yards. The British Study reinforced this by discovering that 90% of the fish recaptured by electro-fishing were within 656 yards of the stocking site 5 - 13 days later. South Dakota was the outlier to the downstream imperative and reported some upstream movement during lower flow periods. While the actual distance moved depends on the specific characteristics of the particular streams studied, the point is that the fish head downstream to a pool or run.

Interestingly, there was no statistical significance related to the presence or absence of environmental factors. While stockers hang longer near suitable structures – logs, boulders, stable banks – they eventually migrate. In total, Pennsylvania considered 20 different variables to determine if any was the prime motivator spurring movement. For those who watch the environment, an immediate assumption might be that water chemistry and temperature would be key drivers. After all, if the water is too acidic or warm, trout should move immediately to seek a better habitat.

Regarding temperature, the 2006 Pennsylvania study did not see this behavior since there was no significant difference between the water temperature of the hatchery, stock truck, and destination streams. They did discover a weak pH correlation and captured more trout within a 300-yard footprint in less acidic areas. In general, trout moved at the same rate regardless of the water characteristics.

What about flow? In the Rapid Creek study, fish immediately migrated downstream when placed in water flowing more than 100 cubic feet per minute. You might think a flood would influence the downstream dispersion, as in "all the fish were washed downstream by the big storm," but that is not the case. Radio-tagged trout held in position during two Pennsylvania floods in 2005. This makes sense. A stocked fish may not be accustomed to strong flows and drift with the current when deposited in a stream running at high volume. Once acclimated and comfortable, trout find protected holding positions to deal with high water conditions. So, the common assumption that fish wash downstream after a storm is untrue. 

Let's solve the puzzle about where to catch trout and how to catch trout. Since you must wait a week or more for the fish to recognize standard fly patterns mimicking natural food, you can assume the stockers will no longer be lying in the accessible spots near the road the stocking truck uses. They are long gone. Knowing the trend is to migrate downstream, here is the simple strategy for success in catching trout. Start 300 to 600 yards downstream of the stocking location and fish back to the stocking point, targeting pools and runs. Since the most intense pressure is in the several days immediately after stocking, you will probably have the stream to yourself by waiting. After all, the stock truck chasers assume the stream is cleaned out when, in fact, the trout have just moved out. To catch trout, you must fish where the trout are. That is simple advice. Knowing when to fish (wait a week or more) and where to fish (downstream near the structure), you can have a good day on the stream - even a stocked stream.