REPORT OF THE COMMISSIONER OP FISHERIES XIX 



COOPERATIVE FISH NURSERIES 



At the principal trout hatcheries the congested condition during 

 the spring months, just after the eggs have hatched, has been re- 

 lieved to a large degree by the transfer of small fish to cooperative 

 nurseries after they have been feeding for from four to six weeks. 

 The nurseries are furnished by fish and game organizations working 

 in cooperation with the bureau. The organizations supply troughs, 

 ponds, fish food, and all equipment, including men to care for and 

 feed the fish. At these nurseries the fish are held in troughs until 

 they are approximately 2 inches in length, when they are placed in 

 the nursery ponds and held until fall for distribution. Fifty per 

 cent of the fish thus produced are turned over to the bureau for the 

 purpose of supplying applications that it has from that region, 

 and the other 50 per cent is given to the club for stocking local 

 waters. 



The cooperative fish nursery arouses the interest of the public in 

 the production and protection of fish, brings financial support from 

 those most interested, reduces the bureau's distribution costs, insures 

 the rearing of a larger number of fry to the fingerling sizes, simpli- 

 fies the distribution of such fish, and promises to be one of the 

 greatest advances made in recent years to keep our streams stocked 

 with trout. 



The production of bass always has been fraught with difficulties 

 not fully understood by the general public. Sometimes applica- 

 tions are received for 1,000,000 bass. At most of the bass hatcheries 

 not more than 5 to 8 acres are used for ponds that usually average 

 from one-third to one- fourth acre in area. It is impossible to pro- 

 duce large fingerling bass and other warm-water fishes in such small 

 areas, as they are wide rangers and require considerable pond room 

 to become large fish. The young fish must have microscopic food, 

 such as daphnia. At a later stage of development the stronger fish 

 prey upon the weaker ones. For organizations with facilities for 

 rearing fish in ponds of 10 to 15 acres a cooperative plan has been 

 suggested. Larger areas would be suitable if the water supply 

 could be so controlled as to prevent flooding and in the fall of the 

 year drained to remove the small fish. The Bureau of Fisheries is 

 not in a position to supply brood stocks for such projects. It can 

 render material aid to sulfh organizations by supervising the con- 

 struction of the ponds and the general work of rearing and dis- 

 tributing the fish. Many organizations may find it possible to set 

 aside suitable areas for bass culture that can be operated under 

 Government supervision. 



Commercial species of fish were propagated on a large scale at the 

 stations located on the Atlantic and Paci£c coasts and throughout 

 the Great Lakes region. Eggs were collected from fish caught by 

 the commercial fishermen or experienced spawn takers furnished by 

 the bureau, and were sent to the hatcheries to be incubated. The 

 resulting fry were released on natural spawning grounds. The 

 bureau has been aided greatly in this work by many of the States. 



