initiated at Hill Lake and Tarentorus trout-rearing stations on the effect of water 

 hardness on the incubation and culture of various lots of lake trout egg stock 

 secured from different natural environments exhibiting different amounts of water 

 hardness, and the pond culture of walleye to the fingerling stage at the White 

 Lake Hatchery. 



No pertinent information is yet available on the investigations to determine 

 the effect of water hardness on the incubation and culture of lake trout eggs. 



Results from the initial attempt to culture walleye fingerlings in hatchery 

 ponds in Ontario are most encouraging. Although some difficulty was encountered 

 from cannibalism immediately prior to the harvest of the fish, an estimated total 

 of 67,000 walleye fingerlings, measuring 1.8 inches in length, were produced from 

 three small ponds (total surface area of 2.2 acres) at an approximate cost of 

 2.23 cents per fish. 



The lake trout rehabihtation programme for Lake Superior was continued 

 in 1961 with the planting of 493,980 marked lake trout yearlings and 60,200 

 marked lake trout fingerlings. As in previous years, the stock was produced and 

 planted from the Tarentorus and Dorion trout-rearing stations and from the Port 

 Arthur Hatchery. An estimated 215,000 lake trout yearlings were marked by the 

 removal of the left pectoral and right ventral fins at the Tarentorus station, and 

 these fish were planted along the northeast shore of Lake Superior in the vicinity 

 of Agawa Bay, Montreal River and Coldwater Creek. Approximately 278,980 

 lake trout yearlings produced at the Dorion station were marked by the removal 

 of the right and left ventral fins, and they were planted in the vicinity of Rossport. 

 The lake trout fingerling stock produced at the Port Arthur Hatchery was marked 

 by the removal of the right pectoral and adipose fins, and these fish were planted 

 along the west shore of Pie Island located at the entrance to Thunder Bay. 



Private Hatcheries 



Nineteen permits were issued to private hatchery operators by the Depart- 

 ment in 1961. These permits, which are currently provided free of charge, 

 authorize the sale of game fish species for restocking purposes, if the planting 

 is approved by the Department. 



Although nineteen permits were issued in 1961, only eleven of the permittees 

 sold any fish. The majority of the sales were made by four of the largest 

 producers. 



The following summary shows the number of plantings and the number in 

 each age class of fish sold by private hatchery operators in 1961. 



SUMMARY OF THE DISTRIBUTION OF FISH 

 FROM PRIVATE COMMERCIAL HATCHERIES, 1961 



120 



