Native fish in Sublette County

Wyoming game and fish photo The orange slash to the underside of the jaw is recognizable on the cutthroat trout native to Sublette County.

Fishing is one of the most popular activities

for citizens and tourists in Sublette

County, although the fish that inhabit our

waters have changed substantially over the

years. When settlers first arrived, some of

the most popular targets of fishermen, such

as brown trout and lake trout, were not a

part of the native ecosystem. Fisheries

management and unauthorized introductions

have changed fish populations and

nonnative species are now the most popular

to catch among fishermen. In many

cases, native species have struggled to survive

the introduction of nonnative fish, but

several natives can still be found in Sublette

County, including the cutthroat trout,

mountain whitefish and roundtail chub.

Cutthroat trout are the only trout native

to the Rocky Mountains and are perhaps

the most well known of the native fish

in Sublette County. They are the official

state fish of Wyoming and they are distinguished

from other trout species by the

red-orange slash on the underside of their

jaw. Lake populations of cutthroats have

been negatively impacted by introductions

of lake trout and stream populations have

suffered from introductions of brown,

brook and rainbow trout. Cutthroats are

aggressive fish that will readily bite flies

and small fishing lures and because of this,

they are a popular target for many fishermen.

These fish were once abundant in

streams and rivers throughout the county,

but now they are found most commonly in

the small streams of the Wyoming Range.

Maintaining cutthroat populations is a priority

for Wyoming Game and Fish, and

they have programs to educate anglers

about cutthroats. One such program is the

“Cutt-slam,” which encourages anglers to

catch (and release) all four subspecies of

cutthroats in Wyoming.

Mountain whitefish are native to the

Green River watershed and are still commonly

found within much of their native

range. Many anglers will catch whitefish

while targeting trout and as a result, the

whitefish has the reputation of being a

“trash fish” among some fishermen. This

reputation is undeserved, as whitefish

are an important part of the ecosystem.

In most cases, they do not compete with

trout for food sources, instead foraging

for invertebrates on the bottom of rivers

while trout feed on drifting insects. Large

populations of young whitefish can also

Native fish in Sublette County

By Brad Blackwell, SCCD Surface Water Program manager

be an important food source for trout and

the presence of whitefish likely means a

healthier trout fishery. Whitefish willingly

bite flies and put up an impressive fight

and on days when the trout are reluctant

to bite, whitefish can make for a great day

of fishing.

A third native fish in Sublette County is

the roundtail chub. Roundtail chub are one

of the lesser-known native fish, but they are

an interesting inhabitant of Sublette County.

Throughout most of their range, the roundtail

chub lives in rivers and streams but in

Sublette County, they occupy several of

the local lakes. These are the only known

lake-bound populations of roundtail chub.

Introductions of other species of fish into

the lakes such as lake trout, brook trout and

white suckers have had negative impacts on

roundtail chub and their population appears

to have been eliminated in Boulder Lake. In

other lakes including Halfmoon and Little

Halfmoon, their populations appear to be

stable despite the introductions of many

other species. Roundtail chub are seldom

targeted by anglers but they will bite flies

and lures and can be a frequent “accidental”

catch in some of the lakes in the region.

Native fish have overcome many odds

to survive but there are ways to promote

the survival of native fish in Sublette


• Don’t move fish – Moving fish from

one body of water to another can lead to

catastrophic consequences. Unauthorized

movement of lake trout into Yellowstone

Lake has led to a collapse in the cutthroat

population and millions of dollars in mitigation

costs. Introduction of white suckers

into Dollar Lake in Sublette County (likely

from use as bait) destroyed the trout fishery

in the lake. Never move fish from one location

to another.

• Target nonnative fish for harvest –

Many people love to catch and eat fish but

some species are better targets than others.

For example, keeping brook trout to

eat and releasing cutthroats keeps native

cutthroats in the streams.

• Contribute to native fish programs

– Wyoming Game and Fish and several

nonprofit organizations have programs to

benefit native fish. Contributing your time

or donations to these programs helps maintain

native fish populations in Wyoming.

– The Sublette County Conservation

District staff provides an article for the

first Tuesday of each month.