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Boulder Fish Rearing Station
Boulder Fish Rearing Station

Boulder Fish Rearing Station
P.O. Box 36, Boulder Rearing Station Road
Boulder, Wyoming 82923

Located 15 miles south of Pinedale on Highway 191,
then 1.5 miles east on Boulder Rearing Station Road

Built on the East Fork River along the west slope of the Wind River Mountains, the Boulder Rearing Station is only a few miles from Highway 191 south of Pinedale, Wyoming. The station sits on 200 acres of land purchased by the Wyoming Game and Fish Department and opened for operation in 1952. The Boulder Rearing Station offers visitors the unique opportunity to view fish culture in progress.

What does the Boulder Rearing Station do?
Boulder Fish Rearing Station

The main focus of the Boulder Rearing Station is care of the Fall Spawning rainbow trout broodstock, but other species raised include Kokanee salmon, brown, golden, Eagle Lake rainbow and Colorado River cutthroat trout. In total, the facility raises approximately 35,000 pounds of fish annually to stock into Wyoming waters.

Where does the station get its water?

Natural springs in the area provide a constant supply of cold water needed for a successful fish rearing station. Water flowing from the springs to the facility fluctuates from a low of 900 gallons per minute (gpm) in March, April and May to a high of 2,100 gpm from June through September. During these peak months the springs provide approximately 2.2 million gallons of water a day at an average temperature of 52oF. After passing over the fish, the water is returned to the East Fork River.

The Boulder Rearing Station Broodstock
and Spawning
Boulder Fish Rearing Station

The Fall Spawning rainbow broodstock held at the station consists of approximately 3,000 fish, weighing between three and six pounds each. The broodstock fish usually become sexually mature in their third year. Normally, rainbow trout spawn or mate in the spring, but Fall spawning rainbow have been manipulated to spawn in the fall. This allows a longer growing season for offspring before being stocked.

Spawning at the station usually begins in October and continues through December. The broodstock annually produces about 3 million eggs. When fish are preparing to spawn they will move upstream in search of suitable habitat. Personnel capture the fish in the raceways by placing a funnel-shaped trap in the water. After the fish are captured they are separated by sex and held until spawned.

Eggs are collected in bowls by gently squeezing the abdomen of a female, with the average rainbow producing 2,200 eggs. The eggs are then fertilized with the sperm, or "milt," from a male. Fish are spawned at a 1:1 ratio to provide the best genetic variability. Fertilized eggs are then placed in large coolers and shipped to many different facilities for hatching. After spawning, some of the fish are held-over for spawning the following year while others are released into various Wyoming waters.

Fertilized eggs are shipped to hatcheries where they are placed in incubators for 20-30 days. When the eggs begin hatching, the fish are initially placed in small troughs for rearing. Small fish are fed frequently; sometimes up to eight times daily.

How does the Wyoming Game and Fish Department
stock fish?
Boulder Fish Rearing Station

Once fish have reached the size requested by fish management crews they are ready to be stocked. Around 300,000 fish are stocked from Boulder each year.

There are several ways fish are stocked. Trucks, barges and even helicopters help the fish reach their final destination. Trucks are the most common way of transporting fish from the facility to a lake or river. Insulated tanks keep the water cool while oxygen bottles and aerators provide oxygen to the fish during transport. Barges with on board tanks are used when fish need to be stocked in a particular part of a river or lake. Helicopters are used when a lake is inaccessible by truck, such as in high mountain lakes in wilderness areas. All spawning, rearing and stocking means better fishing for anglers in Wyoming!

Trout fishing near the rearing station is available at two ponds located near the station and along a one-mile stretch of the East Fork River.


Wyoming Game & Fish Department Headquarters
5400 Bishop Blvd. Cheyenne, WY 82006
ph: (307) 777-4600
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