REPORT OF COMMISSIONER OF FISH AND FISHERIES. LXV 



are especially satisfactory. The eggs of the whitefish were obtained 

 tliis year in the usual manner ; that is, from the ripe fish found in the 

 nets of the fishermen. This plan is satisfactory only when all the con- 

 curring circumstances are favorable. Bad weather may interfere so as 

 to destroy any possible chance of success. Mr. Clark now states that 

 experiments have demonstrated the feasibility of holding the immature 

 spawners in confinement until every egg has been secured, thus making 

 it possible to save the entire crop of eggs not deposited by the fish 

 themselves. The greater part of the eggs at the Detroit hatchery during 

 the season were obtained in this way ; and those eggs which were taken 

 from fish brought from Lake Erie iu casks, and held in tanks in the 

 hatchery till they had matured, were found to be the very best pro- 

 cured at Northville. The improved condition of the eggs is due to the 

 fact that by the new method much greater care is possible, and the 

 hurry and confusion of pound-net operations is avoided. Mr. Clark 

 hopes next year to follow this method to the exclusion of every other. 

 The eggs of the lake trout were obtained from the fish taken in gill- 

 nets, and then shipped to Northville. The weather at the time w^as 

 warm and many of the eggs arrived in Northville in poor condition. 

 By the experience gained this year, and the improved facilities, it is 

 hoped that a much better showing, both as to quantity and quality, will 

 be made next season. The total number of lake-trout eggs taken was 

 277,000. Besides the usual number of transmissions to persons in the 

 United States, a number of these eggs were sent to the Deutscher Fisch- 

 erei-Verein of Germanj' and the Soci6t^ d'Acclimatation of France. 

 Mr. Clark also hatched out a number of trout eggs received from Ger- 

 many. There were 5,000 iu all, and they reached Northville on'the 26th 

 of March. The greater number of them were too far advanced to hatch 

 out satisfactorily. A considerable portion, however, reached maturity, 

 and are now doing very well indeed. They are quite as large as our 

 own trout of the same age. Mr. Clark reports a failure with regard to 

 the propagation of the rainbow trout — the first serious failure that the 

 Northville establishment has made. Only 45,000 eggs of this species 

 were obtained, of which but 15 per cent, could be fertilized. The num- 

 ber of fish hatched was C,400. He is somewhat at a loss to discover 

 what was the cause of the difficulty, but is inclined to attribute it to 

 the abnormal character of the fluid surrounding the eggs. He sug- 

 gests as another possible explanation that the parent fish were overfed, 

 and that the inflow to their pond gave them a current too slow and fee- 

 ble, the result being that they became too inactive. He proposes here- 

 aiter to try the experiment of reducing their food allowance to the 

 minimum and placing them in a good current of water iu one of the 

 new ponds. Such treatment would seem to be in accordance with their 

 natural habits. Twenty thousand eggs of land-locked salmon, from 

 Grand Lake Stream, Maine, arrived at this station Marchl2, and were 

 hatched out satisfactorily. The loss was trifling. They were distrib- 

 S. Mis. 46 V 



