Hatchery-raised trout and stupid are basically synonymous in the days following stocking. Hordes of anglers line up along designated trout streams with corn, cheese, and sometimes even plain old hooks to catch easy limits. The ignorance doesn’t last long, though, and old stocked trout can be some of the hardest fish to trick.
The Day of Stocking
Immediately following stocking, hatchery-raised trout will school up in huge numbers. These groups rarely venture far from where they were stocked in the first couple days, preferring to swim almost aimlessly right next to shore. The trout are simply acting the same way they did at the hatchery, and they relate to the stream edge similarly to how they related to the raceway edges. Some studies have even noted that trout stocked in lakes prefer to swim about 18 inches below the surface or 18 inches above the bottom, which is the average depth of a hatchery raceway.
Catching trout now is basically guaranteed. The giant schools are easily spotted from far away, and the fish don’t shy away from approaching humans (after all, their caretakers passed over their raceways frequently at the hatchery). Inexperienced and perpetually hungry, these trout will bite on practically anything.
One Week After Stocking
In just three to ten days after stocking, stocked trout will have entirely dispersed from their stocking site. They will mainly travel downstream, but biologists say that this isn’t a result of being washed out; the trout are able to hold their position in fast water and flood conditions almost immediately. On average, trout travel about three miles downstream from the stocking site and about three quarters of a mile upstream. However, one study in Pennsylvania followed a trout that traveled over 100 miles from its stocking site.
Regardless of their ability to travel, stocked trout are still woefully ignorant of their streams’ food options. Stomach content studies show that trout at this stage will swipe at anything small, brown, and on the surface. Acorn bits, twigs, dead leaves, and drowning insects all trigger the same response.
One Month After Stocking
After a month, the trout will be even more widely dispersed and settled in. The biggest factors in how a trout chooses its habitat, it seems, are water temperature and bottom substrate. Distance from the stocking site has a surprisingly minimal effect on a trout’s final range. In fact, wild trout exhibit much higher site fidelity than do stocked trout. Conspecific density also plays a minor role in final location, which means that one small section of stream can hold a shocking amount of trout.
Now stocked trout will be reasonably practiced at determining whether or not something is food. That’s not to say that they share the same diet as wild trout yet, though. Studies show that stocked trout – and brown trout especially – feed almost exclusively on food at the surface rather than anything on the bottom or throughout the water column.
This usually translates to a diet rich in adult terrestrial insects, and not much in anything else. Wild trout, comparatively, eat mostly aquatic larvae and nymphs. When fishing during the months that follow stocking, don’t worry about sorting through endless tiny nymph imitations to match the hatch. Anglers still have luck with bladed lures and Powerbait but can also start to get reactions from dark dry flies.
One Year After Stocking
Trout continue to increase their range as they spend more time in the stream. It is not uncommon for one individual’s territory to double between its first year after stocking and its second. As such, older stocked trout are far more mobile and may not stay in any particular area as long as a younger trout might.
Although survival plummets for stocked trout as time goes on, the tough fish that last year after year are completely acclimated to stream life. These trout are skittish around people and much harder to fool. When targeting these jaded individuals, treat them as you would wild trout: with subtle approaches and delicate flies.
Originally published in Outdoor News Minnesota.