Tillett Springs Rearing Station

Tilliett Springs Rearing Station

Tillett Springs Rearing Station
P.O. Box 416, 195 County Road 16
Tillett, Wyoming 82431
ph: (307) 548-6650

2.5 miles east of Lovell on U.S Highway 14A, then 8.5 miles northeast on State Highway 37. Continue 5 miles on Crooked Creek Road.

Located on the western slope of the Big Horn Mountains, Tillett Springs Rearing Station is approximately 17 miles northeast of Lovell, Wyoming. The rearing station was constructed in 1958, and named for the Tillett Ranch. The ranch owners granted a 99 year lease for $1.00 to the Wyoming Game and Fish Department for the property. Located a short distance from the Pryor Mountain Wild Horse Range and Bighorn Canyon National Recreation Area, this facility offers visitors scenic beauty as well as the opportunity to view fish culture activities.

The main focus of the rearing station is the care and maintenance of the Fire Hole Rainbow brood stock, but other species raised include brown trout and Snake River cutthroat trout.

Where does Tillett Springs get its water?

Two natural springs provide an excellent source of water supplying 1,380 gallons of water per minute at a constant temperature of 54 F. Tillett Springs Rearing Station has one concrete pond, two dirt ponds, and 12 concrete raceways, 5 feet wide and 100 feet long to raise fish. Fish are grown to stocking size in the concrete raceways and one of the dirt ponds. The concrete pond and second dirt pond are used to house the Fire Hole rainbow brood stock.

The Fire Hole rainbow brood stock held at the station consists of approximately 2,700 to 3,100 fish weighing on average between 1.5 to 3 pounds. The brood fish usually become sexually mature in their third year. This brood stock came from the Fire Hole River in Yellowstone National Park.

How does Tillett Springs spawn?

Spawning at the station usually begins in November and continues through January with the brood stock annually producing about 1.6 million eggs. When the fish are preparing to spawn they will travel upstream in search of suitable habitat. Personnel take advantage of this natural movement to capture spawning fish by placing a funnel-shaped trap in the raceway between the brood pond and spawning pens. After the fish are captured they are separated by age and sex, and held until spawned.

Eggs are collected in bowls by gently applying pressure to the abdomen of the female, with the average rainbow producing 1,500 eggs, the eggs are then fertilized with the sperm or “milt” from the male. Fish are spawned at a ratio of 1:1 (male to female) to provide the best opportunity for maintaining genetic diversity. Fertilized eggs are then placed in large coolers and shipped to other facilities for hatching. Tillett is a rearing station and does not have the equipment to hatch fertilized eggs. After spawning, the fish are released unharmed to spawn again next year. Fertilized eggs are placed in incubators for 20 to 30 days. When the eggs begin hatching, the fish (fry) are then placed in small troughs where they begin growing. Small fish are fed frequently, often as many as eight to ten times a day.
In 1994, an isolation hatchery was constructed at Tillett to give the station the ability to raise fish of undetermined disease status. The primary function of the isolation hatchery is to incubate and hatch eggs collected from wild brood sources. The eggs and fish are kept isolated from all other fish on the station until they pass disease inspection. 

After passing the inspection the fish can then be transferred to other rearing units on the station, or to other hatcheries in the state to be reared for stocking. Our isolation hatchery has been used to hatch Yellowstone cutthroat eggs taken from the Le Hardy Rapids in Yellowstone National Park, golden trout eggs, brown trout, and tiger trout eggs.

How does Tillett Springs stock fish?

Once fish have reached the size requested by fish management crews they are ready to be stocked. The Wyoming Game and Fish Department only stocks fish in waters where there is suitable habitat and public fishing is allowed. Around 170,000 fish are stocked annually from this facility.

There are several ways fish are stocked. Trucks, boats, and even helicopters help the fish reach their final destination. Trucks are the most common way of transporting fish from the facility to the lake or stream. Insulated tanks keep the water cool while oxygen bottles and aerators provide oxygen to the fish during transport. Boats with onboard tanks are sometimes used when fish need to be scattered through particular parts of streams or lakes. Helicopters are used when a lake is inaccessible by truck, such as in high mountain lakes in wilderness areas.

The Tillett Springs Rearing Station serves the Wyoming public, as well as other states, by providing high quality fish for anglers. This helps insure angling opportunities for the present and future generations.
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