How Fish Are Stocked in Colorado

If you’ve ever gone fishing in Colorado, then you’ve probably been to a lake or river that’s been stocked with fish by the state’s department of natural resources. More specifically, the Colorado Parks and Wildlife agency. 

Stocking fish has been practiced all over the country for over a hundred years, whether done by private citizens or by state governments. The rules and regulations have changed a lot since the early days of stocking, especially as scientists have become more aware of the environmental impacts of certain stocking practices. 

Here’s a bit about fish stocking, the benefits and drawbacks of it and, of course, how it’s done here in Colorado!

How and why do they stock fish in Colorado?

Why are lakes stocked with fish

Stocking lakes with fish is a practice that’s done all over the United States, from small ponds and lakes in Midwest to alpine behemoths up in the Colorado Rockies. 

There are two reasons to stock lakes with fish. First, it’s done to supplement or increase already existing populations of fish that, for whatever reason, are facing a decline in population. This may be due to drought, lack of food, overfishing or because of conditions that prevent the fish from breeding. The second reason is that there may not be a fish population there at all, so stocking a lake with fish may be the beginning of a brand new generation of fish in that ecosystem.

Stocking lakes or ponds with fish dates back at least a few hundred years to the early 1800s. For the majority of the 19th century, trout stocking was done to enhance sport fishing in popular areas and in up-and-coming fishing areas. There was little to no regard for the ecological and environmental impacts of introducing large populations of trout to lakes, especially since the locations and the number of fish being stocked wasn’t well recorded. 

It was only in 1871 that the U.S. Fish Commission was established, which coincided with the rising interest in stocking non-native fish into rivers, streams and lakes for both sport and food. Researchers at the commission studied the decrease in food fish populations in the country and, with a hefty grant from Congress, developed food fish stocks for non-native fish like carp, striped bass, rainbow trout and salmon in waterways all around the country. 

Until the mid-1900s, fish stocking was done to introduce as many fish as possible to a given system for the sake of both food and sport. The Wilderness Act of 1964 presented research that suggested stocking lakes with both native and nonnative fish had serious impacts on other organisms, resulting in greater attention to the number of fish being introduced and where they were being introduced to. 

Today there are both benefits and drawbacks to stocking fish. Lakes that are naturally fishless — like many alpine lakes, for example — are usually home to great invertebrate and amphibian populations, both of which can be devastated with the sudden appearance of predators they had never had to deal with before. And with any form of natural resource, playing around with the natural food chain of an ecosystem generally affects everything else, too. 

And while there are significant environmental impacts to the practice, there are also some benefits to stocking fish in lakes and rivers. For one, stocking native fish into naturally-populated bodies of water can bolster endangered populations. Stocking fish into popular fishing spots also keeps anglers and sport fishers in the areas that have been deemed acceptable for fishing which, in turn, keeps more delicate areas protected. 

Nowadays, there is far more thought put into the practice of fish stocking, both by private organizations and by the government. Regulations and legislation around fish stocking varies from area to area and, in most cases, requires scientific research into the environmental impact of fish stocking. You can find out about the stocking regulations for each state by visiting their Department of Natural Resources website, like the Colorado Parks and Wildlife website!

Fish stocking in Colorado

The state of Colorado does stock fish in certain waters, but there are fairly strict regulations on how to use these waters and even stricter fines on those who illegally stock fish!

The Colorado Parks and Wildlife (CPW) agency uses lake and stream surveys to guide their fish management which, in turn, determines how much of a fish to stock or whether to stock at all. Existing populations and their surrounding ecosystems are taken into account, as well as any illegally-stocked fish that could threaten stocked populations. 

Based on the data collected, the hatcheries managed by the CPW can tweak how many fish they breed, where they are distributed and even the size of the fish being introduced to Colorado’s waters. Different waters also have different fishing regulations — some are catch-and-release, some are catch-and-keep, some have bag limits and some have few if any regulations at all. Waters vary from being stocked often to never. The best way to know what you can do in any given body of water is to check the website!

How are rivers and lakes stocked with fish

Most of the time, fish are transported from hatcheries to their new homes in large water tanks and released into the water. This is the standard method for stocking rivers and most lakes.

But what about alpine lakes? As in, the ones you hike up to with a fly-fishing rod in your backpack?

Back in the day, fish had to be transported in milk cans filled with water and sloshing around as a hiker or a horse rider made the trek up to an alpine lake. Nowadays, fish are dropped out of an airplane flying low over the lakes — a process that can release thousands of fish at a time into lakes and waterways. These fish are small enough that the 100-foot tumble through the air doesn’t kill them, but after around 2 years they are large enough to meet the 10-inch catch size!

The CPW stocks over 24 lakes that all sit above 10,000 feet in elevation using this method, giving anglers those unique opportunities to fish in the towering shadows of the Rocky Mountain peaks.

How to find out where fish are being stocked 

You can find out which waters have been stocked with catchable trout by checking out the stocking report on the CPW’s website. It has weekly updates on what lakes or rivers were stocked, giving you the most up-to-date info on where to find the best fishing spots around!

So, if you live in or near our luxury Denver apartments, then you’re probably not too far from a stocked lake, stream or river that’s just waiting for you to visit!

Enjoy!

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Featured photo courtesy Pixabay/K_Malik