1086 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [2] 



based on observations made exclusively in tlie morning, from 5 to 7 

 o'clock, generally precisely at 6. Midday temperatures were undoubt- 

 edly higher. 



The recapture of the salmon in October was successfully accomplished, 

 but four fish eluding us ; 358 of both sexes were manipulated, 233 

 females and 126 males. The females (135 were measured) averaged 

 33.37 inches in length } 15.67 pounds in weight before spawning, 11.85 

 pounds after spawning. The males (71 were measured) had a mean 

 length of 34.8 inches and a mean weight of 13.6 pounds. There were 

 obtained 515 pounds of spawn, counting as afterwards ascertained, 

 2,693,009 eggs. The average yield was 11,608 eggs from each female. 

 As compared with former experience, these means are all much higher, 

 indicating the accuracy of the estimate of weight made when the salmon 

 were purchased. The first eggs were taken October 26, the last Novem- 

 ber 17. 



At the hatching we had, previous to this season, used water directly 

 from the brook, tapping it within 50 feet of the house. The original 

 supply is from " Craig's Pond," a very pure natural lakelet as cold as 

 ordinary lakes in this latitude. But a few hundred feet above the 

 hatchery it receives the waters of some copious springs which have the 

 effect of maintaining a high temperature in the lower part of the brook 

 during the early part of the winter, and thereby forcing the eggs into 

 early development. In 1879 and 1880 we were forced to pack and ship 

 the most forward lots of spawn early in December — a very inconvenient 

 date — and all of them were ready for shipment earlier than it is sup- 

 posed would be best for the young fish, if hatched in northern local- 

 ities. In the winter of 1880-'81 a temporary hatchery was constructed 

 on the brook above the point where the springs enter, to retard the 

 development of a j)ortion of the spawn, and served an excellent pur- 

 pose, although it was in many respects unsatisfactory. It appeared on 

 the whole advisable to conduct a supply of cold water into the main 

 hatchery, and an aqueduct was projected, tapi)ing the brook above the 

 springs. This was executed in August and September, 1881. It was 

 built of cement mortar, laid around a wooden core four and a half inches 

 in diameter, the core being drawn ahead as fast as the cement set. It is 

 believed to be practically permanent, being laid at the bottom of a trench 

 below the reach of frost. It is about 1,600 feet long, and cost $737.30. 

 In the hatchery we have, therefore, a choice, during late fall and early 

 winter, between warm and very cold water. 



In 1881 the spawn was kept at first wholly in the aqueduct water, 

 which had a mean temperature through November of 40.7° F., and 

 through December of 35.2° F. The brook, meanwhile, had a temper- 

 ature of 47.4° F. in November and 41° F, in December. The lower tem- 

 perature of the former enabled us to hold back the earliest eggs until 

 the middle of January, more than a month later than in 1880. 



The first shipments were made January 16, 1882, and to suit the con- 



