Imagine an iridescent green background. Paint vibrant blue circles with bright red spots in the center. Add a shock of orange on the bottom of the canvas and yellow worm markings on the top, and throw a few small gold circles throughout. Make the canvas shine with its own light, and you have a brook trout. Multiply that beauty by ten and you have a spawning brook trout.
In the midwest, where I learned to flyfish on small streams, brook trout are native. In the West, brook trout were introduced in the early 1900’s, along with brown, rainbow and lake trout. These trout were stocked by fishermen for sport, and each species thrived in the clear, cold, and productive waters of the West. Brown and lake trout pose the largest threat to native populations of cutthroat trout, but brook trout also contribute to pressure on cutthroat populations.
As a way to manage introduced species, the Wyoming DNR either places very high limits or no limits at all on the number of fish anglers can keep. In parts of Yellowstone, anglers are required to kill any lake trout that are caught. Lake trout are a particularly large problem because of their voracious appetite and their ability to spawn in stagnant water. Both of these factors, combined with a rapid growth rate and a tendency to feed on smaller cutthroat trout, make lake trout the largest threat to native cutthroat populations.
Although the brook trout are non-native to Wyoming and they too exert pressures on native cutthroat populations, their beauty is stunning. Every fish is unique, with distinct patterns and shades of color. Some have pure white bellies, some have gold bellies, and others still have black bellies. Some trout have a darker green background and others have a bright green background. The males have a hump on their back and black mouths while spawning. Regardless of the color palette, each fish is a hidden treasure, just a curve of dark green sliding through the water, until an angler is lucky enough to reveal their hidden beauty, even just for a moment.