BIOLOGICAL STATION, FAIRPORT, IOWA. 9 



or fail from other causes to reach maturity. However, it is the 

 larofo number which can be infected on fish and liberated at small 

 expense that justifies a confidence in the accomplishment of com- 

 mensurate benefits. The average cost per 1,000 glochidia artifi- 

 cially infected on fish in the fiscal year 1920 was less than 6 cents, 

 inclusive of overhead expenses. 



Some of the streams m which this work has been carried on are 

 the Mississippi River, at various points, the Ohio and Cumberland 

 Rivers, the Wabash River in Indiana, and the White and Black 

 Rivers of Arkansas. 



In connection with the propagation of mussels, many fishes are 

 rescued from land-locked ponds and restored to the rivers. In 

 this way, during the fiscal year 1920, 36,442 adult and 871,553 

 fingerling fish were preserved from probable death by suffocation 

 with the drying up of the temporary ponds, and this benefit was 

 accomplishecl practically without expense additional to that neces- 

 sarily incurred for the propagation of mussels. ^ 



WHAT IS DONE FOR FISH CULTURE. 



The services of agricultural and experimental stations to the 

 farmer are so well understood that large appropriations are annually 

 made by the Federal Government and by every State in order that 

 there ma}^ be conducted the various sorts of investigations and ex- 

 periments that are necessary to assist the farmer in producing larger 

 and better crops with the greatest degree of economy. It is like- 

 wise important that studies and experiments be carried on to in- 

 crease the productiveness of streams and lakes and ponds. The 

 grower of fisnes is even more dependent than the land farmer upon 

 guidance from governmental experiments. A wheat grower or a 

 cattle raiser has some chance to try out various methods and ascer- 

 tain the effects by watching the growth of his crops or of his stock. 

 The fish farmer, on the other hand, may try different methods, but 

 he can not see how they work. Furthermore, nearly all of our 

 water areas are under public and not private ownership and control, 

 and only the public is justified in expenditures for experimental 

 work. 



Nearly all that we know of fish culture in America has been learned 

 in connection with practical fish-cultural stations, where, since the 

 establishment of the United States Fish Commission 50 years ago, 

 many experiments have been carried out. The accumulated experi- 

 ence of keen and observant fish-culturists is of inestimable value- 

 yet it should be pointed out that the function of a fish-cultural 

 station is to produce as large as possible an output of fry or fingerling 

 fish to be distributed in various waters where others must assume the 

 responsibility for bringing the fish to maturity. It is not the pur- 

 pose of such stations to work out by tedious experimentation and 

 careful studies the conditions necessary to make individual ponds as 

 productive as possible for market fish. As yet no other station of the 

 Federal Government than Fairport has been designed to serve this 

 function. 



' During the first half of the fiscal year 1921, through the cooperation of the National Association of 

 r.iitton Manufacturers, more than 5 million fishes taken in the Bureau's rescue work along the Tpper 

 iisslssippi River have been inlccled with mussels and liberated. 



