California Department of Fish and Wildlife

Moccasin Creek Trout Hatchery

Location and Hours

The entrance road is on Highway 49, near the junction of Highway 120, 20 miles south of Sonora. (Tuolumne County)

Open to the public: 7:30 am to 3:30 pm daily


In the 1950’s, several smaller and older fish hatcheries, operated by the California Department of Fish and Game, were closed down and hatchery operations moved to larger more efficient operations. The Basin Creek (Tuolumne), Yosemite, Bass Lake (Madera), Kings River and Visalia hatcheries were closed and replaced by the new San Joaquin Hatchery (on the San Joaquin River) and Moccasin Creek Hatchery.

The Moccasin Creek Fish Hatchery is located on property leased from the City and County of San Francisco. Water is taken from the afterbay of the Moccasin Creek Powerhouse Reservoir, which is part of the Hetch Hetchy water and power system. The Moccasin Hatchery is able to operate with the assistance of the city of San Francisco and the Hetch Hetchy system who provide low cost water and power, which in turn provides recreation to California anglers.

In 1954, the hatchery opened with 24 dirt ponds. Over the years, the hatchery has expanded to include 48 concrete ponds, each 100 feet long. The hatchery building originally consisted of 88 troughs and 6 redwood round tanks. In 2011, 10 deep tanks replaced 20 troughs and in 2012, the redwood round tanks were replaced by 6 deep fiber-glass round tanks.


Fish eggs are currently received from other state hatcheries in winter, spring and late summer. With water temperatures ranging between 43 and 55 degrees Fahrenheit, it takes approximately 14 months to produce a catchable half-pound Rainbow Trout at Moccasin.

After a 3 month stay in the hatchery building, the fry/fingerlings are moved to the concrete ponds where they’ll remain for eleven to twelve months until planted. During their stay in the ponds, they are thinned several times, graded and their health is monitored.

During the course of the year, hatchery personnel will feed the fish approximately 550,000 pounds of feed in varying sizes, with small powder going to the fry and pellets going to the larger fish.

Fish planting out of Moccasin Creek Hatchery is a year-long activity, but 75% of the fish are planted from the first of April to mid-September. Depending on the State’s budget, Moccasin Hatchery produces between 300,000 to 500,000 pounds of fish yearly, roughly 800,000 to 1.2 million total fish. Moccasin Creek is responsible for planting catchable trout, which consist of Rainbow Trout, Brown Trout and the Lahontan Cutthroat Trout, in selected rivers, streams and lakes in Tuolumne, Stanislaus, Merced, Mariposa and portions of Calaveras, Alpine, Madera, Contra Costa and Alameda counties.

Each year, the hatchery managers meet with fishery biologists to allot stocking numbers for each water. Fishing pressure, return rate to angler, water flow and temperature, habitat and public access are all taken into consideration when determining the number of fish each water will receive.

All distribution tanks, which are mounted on trucks, use compressed oxygen and 12-volt recirculation pumps to keep the fish alive. The tanks are well insulated and, after initial cooling of water with ice, will carry fish for many hours without a noticeable rise in temperature. Trout are usually transported in 45 to 48 degree Fahrenheit water. There are no drugs used to immobilize the fish during transportation.

Every couple years, in July, Moccasin is involved with stocking High Sierra lakes by airplane. Many lakes in the Emigrant Wilderness Area are planted with fingerling Rainbow.

In 2011, Moccasin Creek Hatchery partnered with the U.S. Fish and Wildlife Service and was designated as the statewide Cutthroat Trout restoration hatchery. Towards the later part of the year, the hatchery will air plant the majority of the Cutthroat Trout by plane and the rest by vehicle in its native watershed.


There is a staff of seven full-time employees and one part-time secretary. During the busier planting months, seasonal positions are added to relieve the workload.

The hatchery staff would like to thank you for your interest in the hatchery and we hope you will visit us.

Contact us:

See also, Central Region Classroom Aquarium Education Program (Salmonids in the Classroom)