Cutthroat trout are named for the bright red-orange streak in the fold under the jaw. Cutthroat are native to mountain streams, lakes, and rivers throughout Idaho. This is the primary reason for its designation as Idaho’s state fish. They are great indicators of water quality, since they prefer very clean, pristine waters. They have been introduced into many of the high mountain lakes. Cutthroat prefer colder water than do the closely related rainbow trout.
Spawning takes place in the late spring in small tributary streams. The female digs a redd in the gravel with her tail. Cutthroat may spawn more than once and with different partners. Both the male and female are aggressive if other fish try to spawn too close to their redd. Once spawning has been completed, the female will use her body and tail to displace gravel upstream of her redd to cover it. They may spawn during the day or night. The eggs will hatch in about five weeks, early in the summer. The small cutthroat trout may live in the stream where they were born, migrate to another stream, or migrate to a lake. In many Idaho rivers, cutthroat will migrate in the fall, over-winter, and move back to their summer home. You may find yourself angling for cutthroat during only one season in order to find cutthroat large enough to catch. Like the rainbow, their size and age of sexual maturity vary. Cutthroat are usually three years old when they spawn for the first time.
Cutthroat trout will feed on aquatic and terrestrial insects. They feed along the surface but may take insects at any level in the water. Larger cutthroat may feed on smaller fish when available.
Brown trout are golden brown in color with large black spots, red spots with pale halos. They are the only trout with both red and black spotting. Young browns have an orange adipose fin.
Brown trout are native to Europe. They were introduced into Idaho waters in 1892. It was not until 1948 that introductions were successful. The brown trout are more tolerant of silt and warm water than native trout and, therefore, has been stocked in areas disturbed by man.
They may be found in rivers, streams, lakes, and reservoirs in the southern part of the state, particularly in the Henry’s Fork River Basin. There are small populations in the Clark Fork River, Lake Pend Oreille, and other waters in the north.
Spawning occurs in October and early November. With her tail, the female digs a shallow depression in which eggs are deposited. After spawning, she covers the eggs with gravel. The eggs hatch the following April. The juvenile brown trout grow quickly for the first three years. As they reach maturity, growth slows. An adult brown might be 4 to 15 years old.
The brown trout are aggressive and territorial, chasing other species away from good cover. It feeds on many different varieties of invertebrates and small fish, both on the bottom and on the surface. Browns forage freely on the surface when mayflies, caddis flies, and stoneflies are emerging. They will also eat other fish.
Rainbow spawn in streams from mid-April to late June. They use areas of gravel, or cobble, depending on the size of the fish. The female rainbow selects a place in a riffle area below a pool to dig a redd (nest). The female displaces the gravel with her body and tail, and the male fertilizes the eggs as they are deposited. The female covers the eggs with gravel by continuing upstream and the current carries the gravel over the eggs.
The eggs hatch in early to midsummer. The young fish may live in the stream a few months, several years, or their entire life. The growth of those that remain in the stream varies with the amount of food and temperature of the stream.
When they mature and are ready to spawn, the rainbow migrates back to the place they were born. The age of sexual maturity depends on the type of rainbow and where it lives. Most rainbows require 3 to 5 years to mature.
The brook trout is one of the most colorful of the trout species. The brook trout is actually a char, characterized by light spots on a dark background. The back is dark green with pale wavy lines; some people these as worm-like markings. The sides are a purple sheen with blue-haloed red spots. There are no black spots on this fish. The pelvic, pectoral and anal fins have white leading edges. Originally native to the eastern U.S. and Canada, the brook trout were introduced into Idaho waters in the early 1900’s. They are now found in many of our streams and lakes.
The brook trout spawn in October and the eggs hatch in the spring. They can first spawn when they are 18 months old and only three inches long. This feature causes many brook trout populations to overcrowd their habitat resulting in individuals becoming stunted in size.
The diet of the brook trout is extremely variable as it includes invertebrates, insects, and fish. Because of this varied diet, many different fishing techniques can take brook trout.
Small spinners or spoons are often quite effective, as are both wet and dry flies. Worms also work quite well. To catch brook trout, the lure should be placed close to cover, such as submerged logs or undercut banks. Once the fish has been hooked, it is important to get it into open water as brook trout are notorious for tangling the angler’s line around logs and rocks.
There are many other fish species in Idaho, but the ones above will really get your attention.