EEPOET OF COMMISSIONER OF FISH AND FISHERIES. XV 



habits of the species ; making the white-fish, the most valuable food-fish 

 of the lakes, the princii)al object of atteution and efiScieut action for their 

 restoration. 



On the 13th of April, 1871, the first visit to the fishing-shores was 

 made, and it became evident from the first, that to obtain any definite 

 knowledge of the amount of decrease, it would be necessary to make the 

 entire circuit of the lake. The migratory habits of the fish and the 

 tendency to entirely change their locality after a term of years, at least 

 in the opinion of the fishermen, made it evident at once that the condi- 

 tion as to numbers could not be understood from any circumscribed 

 area of shore, but that a collection of accurate statistics through a 

 term of years for all the fishing-regions must be gathered to give sat- 

 isfactory evidence as to their condition. 



The southern end of the lake was visited from point to point by 

 steamer and rail before the middle of summer, and, at the northern end, 

 where no steamers plied, the tour was made in an open boat, the trip 

 lasting about five weeks, the sum of the distances4;raveled from point to 

 point being about six hundred miles. Seventy-one stations were visited, 

 embracing nearly the entire number of fisheries. 



Though recorded statistics in the fishing localities were rare, still good 

 evidences were obtained of the decrease and its causes, and many inter- 

 esting notes of the habits of species and their mutual relations pro- 

 cured. Information was constantly sought and obtained, from fishermen, 

 dealers, and residents, on the subject of the fisheries, which was noted 

 for use in preparing a report on the subject of the inquiry. 



As on several other occasions, very important assistance was rendered 

 by the Secretary of the Treasury, the revenue-steamer Andrew John- 

 son, Capt. David Evans, being instructed to afford facilities for examina- 

 tion of the bottom fauna of the hike. In September Mr. Milner went 

 on board with a dredging outfit, and remained during a cruise of two 

 weeks dredging in depths of from 30 to 144 fathoms, obtaining a full 

 collection of invertebrate forms from the bottom and some knowledge of 

 the temperature at those depths. The species collected were examined 

 by Dr. William Stimpson; but soon after they were received at the Chi- 

 cago Academy of Sciences, they were lost in the great fire of October. 



The dredge was also used from a small boat in Torch Lake, of the 

 Grand Traverse Eegion, Michigan, in^40 fathoms, and the same forms of 

 Mollusca, Bfysidce, and Gammaridw were found as in Lake Michigan. 



The inquiry was renewed in the latter i^art of June, 1872 ; the region 

 of Lake Superior was explored, collections and notes ware obtained? 

 ahd similar inquiries were made with reference to numbers of fishes. 

 Much less evidence of decrease in this lake was the result, though a 

 marked diminution was ascertained to have taken place in certain local- 

 ities. 



In the autumn of 1872 nearly a million of white-fish eggs were ob- 

 tained by Mr. Milner and placed in Mi;. K W. Clark's hatching-house at 

 Clarkston, Mich., from which in the winter a large number were for- 



