PROPAGATION AND DISTRIBUTION OF FOOD FISHES, 1924 427 



carried throughout its length and deposited over the entire pond 

 area. Roily water during the nesting season of the bass is very in- 

 jurious, as the majority of the eggs with which it comes in contact 

 are usually smothered. Under the new arrangement the deposits 

 are confined to a limited area around the outlet, and the outcome of 

 the past season's work showed a marked increase over recent years 

 in the production of pondfishes. 



The soft mud deposited in several of the ponds had enabled the 

 growth of water lilies to become firmly established, and the smaller 

 plant forms, which serve as nurseries for the development of natu- 

 ral food for young fish, were in danger of being choked out. In ad- 

 vance of the spawTiing season the mud deposits were removed, and 

 the result was a noticeable decline in the growth of lilies. 



The rainbow-trout spawning season extended from October 15 to 

 March 7, during which period 944,000 eggs were collected. In ad- 

 vance of the spawning period the brood trout were segregated into 

 five lots, according to age, with the view of keeping an accurate 

 record of the eggs from each lot, such information being desirable 

 in the selection of eyed eggs for shipment. 



Lot 1 comprised part of the fish over 5 years old; lot 2, 5 3^ears; 

 lot 3, the remainder of the fish over 5 years; lot 4, 3 years; lot 5, 2 

 years. Lot 1 yielded 49S,G00 green eggs, or 51 per cent of the total 

 collection. With a few exceptions, however, they were of very poor 

 quality, particularly in the early stages. The loss amounted to 38.5 

 per cent. Lot 2 produced 112,400 eggs, on which there was a loss 

 of 38.8 per cent. Lot 3 produced 48,950 eggs, and the loss amounted 

 to 35.5. From lot 4, 175,500 eggs were secured, on which a loss of 

 32.2 was sustained. Lot 5 yielded 20,150 eggs, and the loss was 

 45.9. As was expected, lot 5 produced the general average of good 

 eggs that is usually obtained in collections from fish 2 years old, but 

 the fry losses were heavier than had been anticipated. 



The experiment undertaken last year of mixing a small amount of 

 iodine with the food given to a lot of adult fish badly affected with 

 thyroid tumor \\ as continued to the close of the season, and there was 

 a very noticeable reduction in the extent of the disease. 



PONDFISH-CULTURAL STATIONS 



The group comprises seven main stations and two substations. As 

 a whole the results of the work were fairly satisfactory, though unfa- 

 vorable weather during the spawning season and inability to obtain 

 an adequate supph^ of suitable brood fishes served to curtail the out- 

 put at some points. The following table gives the aggregate output 

 of these stations by species during the fiscal years 1923 and 1924: 



