Tips for Streams with Low Fish Density

Lets take a look at how we approach rivers based on fish density and discuss what fishing rivers with fewer fish per mile have to offer

Wading and fly fishing the Gunnison River, Colorado
Wading on the Banks of the Gunnison River, Colorado

April 2023

For the longest time, we picked fishing trips based on a river's fish density. Maybe not even knowingly, but the famous popular stretches of Western rivers are usually known for their high fish counts. Derived from electroshocking surveys, state fishery agencies usually publish information about how many trout per mile are found in a river, and anglers take notice. After all, these rivers offer greater angling opportunities than alternatives with few fish per mile. So we would solely focus our efforts on these rivers, our Blue Ribbon or Gold Medal streams. I don't think we are alone either, how many anglers specifically plan trips to places like the Green River below Flaming Gorge because of its unprecedented trout per mile count? The Green is indeed a fishbowl, and places like this are the angling meccas of the West.

BUT... sometimes this restricts our vision, and rivers with lower density fish counts are perceived as not worth the time. More recently, I've had a change in philosophy. Through reluctant practice (avoiding crowds) I've learned to appreciate lower density river sections, and specifically what we miss out on by ignoring these places. Let's take a look at how we approach rivers based on fish density and discuss what fishing a river with fewer fish per mile has to offer.

Approaching High Density Trout Streams

When fish see lots of food, a good imitation is required

Our beloved rivers, the Blue Ribbon and Gold Medal trout streams of the West have had plenty written about angling strategies but can be summarized below:

  • Rivers with high fish counts produce enough food to grow lots of trout
  • Fish can occupy a wide variety of habitats, and anglers can find fish in almost any suitable holding water during summer months
  • Competition amongst trout can lead to extended periods of active feeding
  • Angling pressure is usually greater: fly presentation is based on subtlety (match the hatch)

There are also some drawbacks to high fish density. For example, the Waterton Canyon stretch on the South Platte has such a high density of trout that very few can outcompete their peers and reach a large size. As a result this stretch is not viewed as a desirable angling destination despite its high density of trout per mile.

Approaching Low Density Trout Streams