THIS IS A TROUT HATCHERY REARING AND DISTRIBUTING TROUT TO HELP MAINTAIN SPORT FISHING UNITED STATES DEPARTMENT OF THE INTERIOR FISH AND WILDLIFE SERVICE Circular 31 U. S GOVERNMENT PRINTING OFFICE : 1955— 0-338844 For sale by the Superintendent of Documents, U. S. Government Printing Office, Washington 25, D. C. - - - - Price 5 cents. THIS IS A TROUT HATCHERY REARING AND DISTRIBUTING TROUT TO HELP MAINTAIN SPORT FISHING UNITED STATES DEPARTMENT OF THE INTERIOR FISH AND WILDLIFE SERVICE Circular 31 U. S GOVERNMENT PRINTING OFFICE -. 1955— 0-338844 For sale by the Superintendent of Documents, U. S. Government Printing Office, Washington 25, D. C. - - - - Price 5 cents. THE PRINCIPAL TROUTS .'ainbow, brown, cutthroat, and brook outs provide most of the sport fishing for rout in the United States. Rainbow and cutthroat (blackspotted) Lrouts are native to the western United States. Rainbow trout have been distributed through- out this country and others. Some of either species may migrate from streams to the ocean or large lakes and return to the streams to spawn. The sea-run cutthroat is called harvest trout ; the sea-run rainbow, steelhead. Both species usually spawn in the spring of the year when water temperatures are rising. In hatcheries, domesticated rainbow brood trout spawn in the fall or winter. The brook "trout" (actually a char) is na- tive to the eastern United States but has been distributed widely. Our widely distributed brown trout were introduced from Europe. Brook and brown trouts spawn in the fall of the year when water temperatures are falling. Food supply and water temperature deter- mine the rate of growth. Size of the female determines the number of eggs deposited in gravel. Trout spawn in the second or third year and in each year of life thereafter. m^-^^i^'^'^-'^^ ,!^••,■(^^• :^^p^ NATURAL LIFE Trout eggs are deposited in prepared redds, or nests in the gravel of stream beds — and hatch in 8 weeks or more. A young fish, or fry, lives for 3 or 4 weeks on food absorbed from the yolk sac. At about the time the yolk is completely absorbed, the fingerling emerges from the gravel and feeds on microscopic aquatic organisms. From the many eggs deposited in the gravel, only a very few young fish are produced and survive to adulthood. Most of the eggs and young fish die from natural causes, such as floods, silt, drought, and predators. Under natural conditions, relatively few trout reach catchable size to be taken by fishermen. HATCHERY OPERATIONS The Fish and Wildhfe Service operates many trout hatcheries in the United States, rearing; brook, brown, cutthroat, and rainbow trout, and some lake trout, as well as the landlocked varieties of Atlantic and Pacific salmon. Trout eggs for incubation in the hatcheries are usually take^. from brood stock reared at the stations. The eggs are taken from the female, fertilized with the sperm or milt from the male, and transferred to the hatchery. The eggs are placed on trays in troughs through which water flows continuously. Well-aerated water at about 50° F. is used for the incubation of eggs. As the yolk sacs are absorbed, the young trout swim up from the bot- tom of the troughs and are fed diets of packinghouse byproducts ; later, livestock feeds are added. -V^ After further growth in outside ponds at the hatchery, the trout are distributed to suitable public streams and lakes to provide fishing for thousands of sport fishermen. WHY THE TROUT HATCHERY ■eking is an important part of fishery management. Hatchery trout are used to vplement natural production. These hatch- eiy trout fill three principal needs under contemporary management practices. 1. A species of trout may be stocked in suitable waters in which it is not present. Such waters include new reservoirs, and waters that have been made more suitable for trout by the removal of unwanted fishes. Other waters not completely barren of fish life may be stocked with one or more trout species to increase the total productivity and contribute to the fisherman's harvest. Fin- gerling trout planted in such environments may quickly grow to catchable size, since an abundance of food is usually available, and, if spawning facilities are adequate, will repro- duce to maintain their population. 2. Trout are stocked in waters that provide conditions suitable for growth but lack facili- ties for adequate reproduction. Many cold- water lakes and ponds are in this category and through proper stocking can provide ex- cellent fishing. Relatively inexpensive finger- ling trout are planted in such waters. Survival is high and they rapidly reach catchable size. Recurrent plants at intervals of from 1 to 3 years may be needed to maintain populations at the proper level. 3. Trout are stocked in waters that lack the productive capacity to meet the local fishing pressure. This is sometimes called put-and-take stocking. Fish of catchable size are planted at frequent intervals and at scat- tered locations. It is not expected that they will grow materially or that many will sur- vive over winter. Most of them are caught during the season in which they are planted. This is the only way successful trout fishing can be provided in areas where the demand for fish exceeds the productive capacity of the waters. Neither State nor Federal hatcheries pro- duce enough trout to meet current demands, so fish are allocated to those areas where the greatest public benefit is anticipated. It is the policy of the Fish and Wildlife Service to allocate or distribute trout from its fish hatcheries in the following order of precedence : 1. Primary obligation will be in the stock- ing of waters on Federal areas, including lakes, streams, and ponds, that are open to public fishing. 2. Secondary obligation will be in the stocking of State waters, including lakes, streams, and ponds, that are open to public fishing. 3. After apportioning the hatchery output to meet the above obligations, any remaining fish may be used to fill applications for pri- vate waters, in which the fish and fishing are not commercialized in any way. So far as possible, the stocking of fish from Federal hatcheries into waters in these cate- gories will be undertaken only after the recommendations of Service and/or State fishery-management biologists have been received on the suitability of water, and the species, size, and number of fish to be stocked. Fishing is a national recreation. About 1 out of every 9 persons in the United States has a fishing license. And there are many more — children and others — who don't need licenses to fish in public waters. Visitors are welcome at all hatcheries of the Fish and Wildlife Service during any day of the week. Employees in attendance will be pleased to answer questions. The Fish and Wildhfe Service is a pubhc agency dedicated to the conservation of the Nation's fish and wildhfe resources. The Service operates salmon, trout, and bass hatcheries for stocking public waters; main- tains wildlife refuges; controls predatory animals; enforces Federal laws for the con- servation of fish and migratory birds; manages commercial fisheries; and engages in fish and wildlife research and related activities. Hhoto by R. W. Coad The Ha3erman, Idaho, unit is typical of many trout-culturol stations. © Shop and storage (D Hatchery building including food storage and preparation (3) Rearing ponds © Office Information about the location of fish hatcheries, and about other activities of the Fish and Wildlife Service, may be obtained from regional offices : Portland, Oreg. ; Albu- querque, N. Mex. ; Minneapolis, Minn. ; Atlanta, Ga. ; Boston, Mass. ; and Juneau, Alaska. . ...ml WHOI Llbrar HSE 00094