BUREAU OF FISHERIES XI 



During 1928 practically all fish ladders in the States of Washington, 

 Oregon, Idaho, and Montana were inspected and studied. Observa- 

 tions were made of the habits of migratory fish to discover the basic 

 principles which should govern the design of fish ways. In 1929, 

 practical application of these principles was made in the construction 

 of a new fish ladder at the Sunnyside Dam near Yakima, Wash., 

 which revealed the efficiency of fish ladders of large pool design. In 

 addition, the design of a new fish ladder for the Sprague River Dam 

 near Chiloquin, Oreg., was begun, studies made of Canadian data on 

 the subject, and several proposed power sites were inspected, including 

 the study of models and designs of fish ladders for the purpose of 

 determining more definitely the requirements at these projects. The 

 examination of proposed power projects and the prompt giving of the 

 specifications necessary for fish-protective structures are of vital im- 

 portance. The bureau has received very helpful cooperation from 

 Federal and State authorities, power interests, and other agencies. 



UPPER MISSISSIPPI RIVER SITUATION 



The upper Mississippi River situation with respect to mussels, fin 

 fisheries, pollution, the possible effects of flood control and improve- 

 ments to navigation, and the importance of properly developing the 

 aquatic resources of the Upper Mississippi Wild Life and Fish Refuge 

 presents a very serious and complex prol)lem. 



Only a few areas from Lake Pepin, Minn., to Quincy, 111., are still 

 productive of nuissels in a commeicial way. The evidence indicates 

 that conditions in the Mississijjpi River within this area are no longer 

 suitable for the development of the glochidia, aiul the nuissel fishery 

 of this region appears to be doomed to economic exluuistion. From 

 Minneapolis to the lower end of Lake Pepin the fisheries situation is 

 bad, the catch of fish in the lake declining from 3,572,000 pounds in 

 1922 to 386,000 pounds in 1929. On February 4, 1930, the metropoh- 

 tan drainage commission of St. Paul and ^Iinnea])()hs rej)orted the 

 oxygen content of the lake water as two and two-tenths parts per 

 million at Frontenac, Minn., near the upper end of tiie lake, and two 

 and seven-tenths parts |)er milhon at Lake City in the lower section. 

 Thus in the upper end of the hike, at h»ast , the oxygen content dropi)ed 

 below the safety point for tlie nuiintenance of lish life. Observations 

 on a number of sloughs ahing the upper Mississippi River in Minnesota 

 and Wisconsin show a reduction of o.xygen content below the safety 

 point. The conditions of the river cited above appear to be due largely 

 to the joint action of ])ollution and erosion silt. 



Conservationists luive stressed the possible dangers to aquatic life 

 whifh may occur through changed conditions resulting from the con? 

 struction of dams and the dredging of dccj)cr navigation channels in 

 this area, and have urged that arrangcnuMits be nuide so that biolo- 

 gists of the Bureaus of Fisheries and Biological Survey will be afl'oided 

 cooperative arrangements for the purpose of calling attention to 

 these potential dangers and suggesting the need for remedial changes. 

 For example, sudden changes in water level may prove very destruc- 

 tive to lish life and detrimental to the birds and mammals of the 

 region. This may impair the value of the Mississipj)i Wild Life and 

 Fish Refuge, as well as nullify the compacts entered into with the 

 Legislatures of Minnesota, Iowa, Wisconsin, and llliru)is and ratified 

 by Congress. 



