Conditions of Experiment 



The techniques, equipment, and methods used in the experiments with 

 blueback salmon have been described in detail by Burrows et al, (1951). 

 No changes in procedure or methods of analysis were made. Each diet was 

 fed to duplicate troughs of fish stocked at 500 grams each in the first 

 experiment and 1,000 grams each in the second experiment. 



In the experiment with chinook salmon certain variations in equip- 

 ment and techniques were introduced. It has been demonstrated by Johnson 

 and Gastineau (1952) that chinook salmon grow at a retarded rate in 

 troughs. The same authors and Palmer et al. (1952) show that in 6-foot 

 circular tanks, chinook salmon grow at the same rate as those reared in 

 large raceways or in Foster-Lucas ponds. The reduction in rate of growth 

 in troughs precluded the use of troughs for diet experiments with chinook 

 salmon. With the transfer of the Salmon-Cultural Laboratory from Leaven- 

 worth to Entiat it was possible to install 6-foot circular tanks in the 

 hatchery. Since it had been demonstrated that this size of tank did not 

 retard the grovirth rate of chinook, it was then possible to conduct feed- 

 ing trials with this species. The circular tanks were substituted for 

 the standard deep troughs in the third experiment. Each tank was stocked 

 with 500 grams of fish, and the diets were fed to duplicate tanks. 



The amount fed per day was determined by reference to feeding charts 

 developed for chinook salmon as shown in Table 1. The percentage of food 

 fed in proportion to the body weight was much less for chinook than it 

 was for blueback salmon at the same water temperature and fish size. 



With these exceptions, the techniques, equipment, and methods used 

 in the three experiments were identical, and comparable to those of 

 previous trials. 



Results of Experiments 



Each of the three experiments was designed for a different purpose. 

 The first experiment was a test of products previously evaluated in 

 feeding trials conducted at this laboratory or by other investigators. 

 Its primary purpose was to develop production diets. The second experi- 

 ment was more exploratory in nature, designed to test new products and 

 to measure their potentialities as components of salmon diets. The 

 third experiment, in which chinook salmon were used, vras designed to 

 determine if differences existed between the nutritional requirements of 

 blueback and chinook salmon and, on the assumption that such differences 

 existed, to attempt to fortify suspect diets to prevent the development 

 of anemia and to increase the growth rate. 



First Experiment, Cold-Water Phase 



The cold-water phase of the first experiment, using blueback salmon 

 as the test animals, was conducted for a 12-week period at an average 



