PROPAGATION AND DISTRIBUTION OF FOOD FISHES, 1921. 29 



HATCHING EGGS IN GRAVEL. 



At the Afognak (Alaska) station an experiment in hatching eggs 

 in gravel after the so-called Kobertson method was undertaken dur- 

 ing the season of 1920. Eggs to the number of 5,500.000 were placed 

 in two old hatching troughs, mixed thoroughly with gravel, and 

 bedded in the bottom of the creek. The troughs were fitted with 

 a cover and water was introduced through a 1-inch pipe leading 

 from a small dam. so that there would be a gradual flow through each 

 trough. The intake of this pipe was carefully protected by a screen. 



On opening the troughs in the spring it was found that very few 

 of the eggs had hatched. Though the winter was a mild one it is 

 probable that the eggs had been frozen, as there had been a very 

 light fall of snow, leaving the creek unprotected, and frost may have 

 penetrated to a greater depth than in seasons of lower temperature. 

 Eggs placed in gravel boxes patterned after the Robertson plan and 

 held in the hatchery developed nicely, and the majority of the fry 

 remained in the gravel until the yolk sac was absorbed. 



SUGGESTIONS TOR POSSIBLE IMPROVEMENT AND ENL^^RGEMENT OF WORK. 



Further extension of the feeding operations at all stations where 

 chinook, sockeN'e, and silver salmons are handled is desirable. This 

 would necessitate an increased allotment for the Pacific coast work, 

 since at the present time there is not sufficient capacity or funds to 

 feed all stock resulting from the eggs collected. In fact, it has 

 been necessary to close certain substations and curtail expansion in 

 all fields. The extension of operations in other fields is essential if 

 the Avork is to be kept at its highest efficiency. The take of eggs at 

 many of our stations has l)een reduced through extensive commercial 

 fishing operations during the period of the war, when heavy demands 

 were made for this class of food, and it will take many A'ears to re- 

 store the streams to their former productiveness. 



The small statutory salaries provided for the lower grades of the 

 bureau's service and the consequent inability to maintain a trained 

 and efficient pei-sonnel have Ijeen important factors in the declining 

 output. Because of these conditions it has been necessary to employ 

 and train new men at most points every season, and as competent 

 men could not be secured or retained at the statutory wage provided 

 station allotments have been drawn upon in many instances for the 

 employment of temporary help at the prevailing high wages, thus 

 greatly reducing the funds available for actual propagation work. 



The returns ifrom the marking of young salmon on the Columbia 

 River and at other points have not been wholly satisfactory. One 

 reason for the small returns from these experiments may be the fact 

 that it has been the custom to hold the fish intended for marking 

 for several months beyond the natural spring migration, and this 

 may have had a serious effect on the life of the fisli iuA'olved. The 

 thought has occurred that better results might be secured if the fish 

 used in the marking experiments are held over one year, or until the 

 migration of the following spring. The results of the marking ex- 

 periments also suggest the desirability of a more thorough study of 

 the early life of the salmon, with the view of correcting any possible 

 weaknesses in present methods of propagation and distribution. 

 Til is is a phase of the work that is respectfully referred to the 

 division of scientific inquiry. 



