262 KEPORT OF COMMISSIONER OF FISH AND FISHERIES. 



The first difficulty was remedied by darkening the windows, wliich 

 was soon followed by the entire disappearance of the conferva ; the sec- 

 ond by raising the trays so as to establish a current underneath thera. 

 By prompt action the eggs that had not yet been affected were saved, 

 but a large proportion of those that retained life long enough to be 

 packed up and sent away had been so seriously injured as to ijerish, 

 either during incubation or soon after hatching. 



11. — PACKING AND SHIPMENT AND DISTRIBUTION OF EGGS. 



During the early part of the season of incubation, with the co-opera- 

 tion of Mr. E. A. Brackett of the Massachusetts commission, I tried a 

 series of experiments designed to determine the period when salmon 

 eggs can be transported with safety. Ten successive packages, each 

 containing eggs froui five separate lots of widely different ages and 

 stages of development, w^ere sent by express to Winchester, Mass., 

 where Mr. Brackett unpacked them and noted the result. The first 

 package was sent on the llth of November, and the last on the 7th of 

 January. The results observed were very uneven, almost total loss at- 

 tending some shipments, while in others the average ratio of loss was 

 quite small. In the first two packages, the germ of the oldest eggs was 

 in i)rocess of expansion over the surface of the yolk, while in the young- 

 est eggs that process had not begun ; in the former the loss was several 

 fold greater than in the latter. In the second package the percentage 

 of loss in the several lots, beginning with the oldest and running down 

 to the youngest, was as follows : 62, 45, 36, 21, zero. In the third lot it 

 was 20, 8, 8, 2, 8. In the fourth lot, the development was but little 

 advanced over the former ones, and the i)ercentage of loss in the several 

 lots remained substantially the same, being, in the order of the age of 

 the lots, 88, 84, 10, 8, zero. The next two packages were badly frozen, 

 and the result therefore indecisive. On the 17th of December, another 

 package was sent, in which the oldest eggs were so far advanced that 

 the heart of the embryo could be seen beating, while the younger eggs 

 had arrived at the same stage as the older ones had in the earlier pack- 

 ages. The relative losses were now reversed, the percentage being from 

 oldest to youngest, zero, zero, 2, 42, 2. A week later another package 

 resulted as follows : percentage, zero, zero, 36, 8. 



The general conclusion drawn from the lesult of these experiments was 

 this : that the critical period, during which salmon-eggs cannot be trans- 

 ported without danger of great loss, begins with the first expansive 

 movement of the germ, and ends with theestablishmentof thecirculation. 

 In our earliest eggs this period was, approximately, from the fifteenth 

 day after fecundation to the thirty-fifth day, ending thirt^^-seven days 

 before the appearance of black eyes. In the later lots, owing to the 

 lower temperature of the water, it was long deferred. In water having 

 a uniform temperature of 44° F. I should think the critical period would 

 begin as early as the tenth day from fecundation, and last two weeks. 



