three years to determine the possibility of developing a source of supply 

 for eggs. 



The salmon have been introdiiced into many other waters. Vermont 

 has done extensive work in the propagation of salmon, but has succeeded 

 in really getting them established in only two lakes, which are connected. 

 New Hampshire had varying success with the salmon at different times 

 and then they disappeared. Maine seems to have kept up the fishing in 

 the original basins M^here these fish were found, and has discovered the 

 danger of trying to have salmon and brook trout in the same lakes. At- 

 tempts to extend the range of salmon to meet the demand of anglers, by 

 planting in lakes of other watersheds than those where they are indig- 

 enous, resulted in salmon fishing but at the sacrifice of the trout ; so they 

 discontinued planting in trout waters. 



Mr. C. O. Hayford, Hackettstown, N. J. : Landlocked salmon were in- 

 troduced in the Rangeley Lakes in 1880, to the detriment of the brook 

 trout. In that section the salmon now predominate in what were once 

 the best brook trout waters and it is very easy to see the reason. Brook 

 trout in the Rangeley section spawn about September 28th, and the land- 

 locked salmon from about October 15th to November 1st, both using the 

 same spawning grounds. Thus when the salmon arrive on the spawning 

 beds and sweep the gravel before spawning, they destroy many brook 

 trout eggs. In four years I probably handled 2,000 salmon, ranging from 

 2 to 18 pounds, and seldom found any difference in the free flow of the 

 eggs from large fish. Once in a while we would get a salmon that would 

 strip very hard. 



Dr. D. L. Belding, Hingham, Mass. : Several important points have 

 been brought out by Mr. Keil in this interesting paper. One of our 

 fellow members. Dr. David Marine, conclusively demonstrated that thyroid 

 tumor may be eliminated or controlled by the use of small quantities 

 of iodine in the water. This work was carried on as part of an experi- 

 mental investigation of the cause of goitre. As far as I know, it was 

 permanently cured. Even if the disease were only arrested, the effect 

 could be maintained by the occasional addition of iodine to the water. 

 At the present time, experimental administration of minute doses of 

 iodine two or three times a year to school children in goitre districts is 

 proving successful. 



Mr. Keil suggested that the reason landlocked salmon were especially 

 susceptible to disease might be due to the lack of a slimy mucous covering. 

 In this connection, the following observation on the effect of copper 

 sulphate on adult brook trout, rainbow trout, and landlocked salmon may 

 prove of interest. All three species were confined in a single pool, which 

 accidentally received the copper sulphate. All the landlocked salmon and 

 over 50 per cent of the brook trout died, while the rainbow trout survived, 

 demonstrating that landlocked salmon were more susceptible to chemical 

 pollution than either of the other species. Possibly Mr. Keil's theory of 

 the lack of mucous covering in landlocked salmon would also explain its 

 susceptibility to pollution. 



At the East Sandwich state hatchery in Massachusetts, chinook salmon 

 matured at the age of four years. Some were allowed to spawn in the 

 pools, and others were stripped. All immediately became covered with 



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