46 DEPARTMENT OF GAME AND FISHERIES No. 9 



neighbourhood of 300,000 fry, of which 241,590 odd were planted in suitable 

 waters. 



The three ponds used as nurseries have a total area of approximately 1.4 

 acres; when they were drained in the fall, 6,353 fingerlings were taken out. 

 The majority of the bass were four inches in length. 



This year the bass in one pond were from domesticated stock, but there 

 was no indication that the yield from these was superior to that obtained from 

 wild bass introduced into the second pond used. In fact, the hatchery manager 

 stated that the opposite was true. It may be that the domesticated stock was 

 not sufficiently well fed during the winter and spring months to be in the best 

 condition for reproduction. 



During the present year systematic observations were made on the limno- 

 biological features of all the Mount Pleasant ponds and collections of bass for 

 stomach analyses were made at frequent intervals. When this material is 

 examined and the results correlated, we should be in a position to state more 

 accurately what our ponds should produce per acre. 



In order to rear fingerling bass in larger quantities a much larger number 

 of nursery ponds is required, and also ponds for the culture of golden shiners 

 and daphnids, the principal forage of bass. 



FEEDING EXPERIMENTS WITH SPECKLED OR BROOK TROUT 



Apart from the general character of the water supply, there is nothing 

 more important than diet in the culture of fish, and in order to study properly 

 the nutritional requirements of trout, an experimental laboratory was established 

 at Mount Pleasant Fish Hatchery in 1929. The initial work in this connection 

 was done by Professor J. D. Detwiler, of the University of Western Ontario, 

 London; during the current year Professor Detwiler, Dr. I. L. Chaikoff, formerly 

 of the Department of Physiology, University of Toronto, and Mr, R. D. Heard, 

 M.A., formerly of the Department of Biochemistry, University of Toronto, in 

 collaboration with the Director of the Branch, continued the problem and the 

 results obtained were presented before the American Fisheries' Society in session 

 at the Royal York Hotel, Toronto, August 27th, 28th, and 29th, 1930, by Professor 

 Detwiler and Mr. Heard. 



One part of the investigation, a brief account of which is given below, was 

 to check the relative values of different kinds of food fed to trout in the hatchery 

 at Mount Pleasant, and also to experiment with other foods with a view to 

 obtaining a more economical diet, which at the same time would be of such 

 nutritional value as to produce good growth and vigorous and healthy fish. 



Experiments with the diets were run in duplicate and included the following; 



Beef liver. 



Beef heart. 



Beef liver and beef heart, half and half. 



Horse meat. 



Beef liver plus dry skim milk, in a ratio of 80 to 20. 



Beef liver plus clam meal, half and half. 



Horse meat plus clam meal, half and half. 



Horse meat plus clam meal plus dry skim milk, in a 



proportion of 60 to 20 to 20. 

 Beef melt. 

 Cooked tripe. 



The fish used in these experiments were hatched during the latter part of 

 February, 1930, from eggs obtained from domesticated stock, Normandale 

 Trout Ponds, near Normandale, Ont. In selecting the fish for these experiments, 

 the largest and the smallest were rejected. 



