22 THE REPORT UPON No. 36 



Our own skilled hatchery officers collect spawn to a large extent in suitable 

 fields and their work is carefully organized in advance. Commercial fishermen 

 also collect spawn and are supplied with the necessary equipment and instructions 

 regarding spawning methods, by the managers of hatcheries in the vicinity of 

 the fishing grounds. 



This year, a survey was made in regard to the methods used by the various 

 fishermen, in connection with the spawning of whitefish in Lake Erie, and 

 these methods were checked with the actual hatch. The percentage of fertile 

 eggs sent in by each fishery was as follows: 63, 62.5, 53, 45, 75, 40, 50, 7, 39. 

 The 39 per cent, was from fish taken in gill nets and the remainder from pound 

 nets. In almost every case the method of spawning was reflected in the 

 results. 



It is relatively an easy matter to rear fish up to the feeding stage, but 

 from the time fish commence to feed trouble begins. It is then that losses 

 commence to be apparent, and in this connection there is no factor apart from 

 the water supply of such importance as food. Trouble in rearing fish, providing 

 the water supply is satisfactory, can be traced to improper diet. Fish culturists 

 are far from reaching a universal agreement regarding what constitutes the most 

 satisfactory diet for trout, but our knowledge is rapidly improving and when 

 biologists, biochemists and physiologists combine to attack the problem, more 

 exact information will be forthcoming. Considerations regarding food supply 

 of fish involve cost, supply available, palatability and the health and vigour 

 produced in the fish. Our own experience has shown that beef liver excels all 

 other fresh meat foods in the diet of small fingerling trout, and that the cheaper 

 products, namely sheep's plucks, pig liver, etc., may be fed satisfactorily to 

 larger fish. 



During the summer Professor J. D. Detwiler, Associate Professor of 

 Zoolog>', University of Western Ontario, commenced a study of the relative 

 importance of fresh meat, fish, and foods of animal and vegetable origin in the 

 diet of trout. 



Speckled Trout: 



By consulting the records on the distribution of speckled trout for the 

 year, it will be observed that there is a decrease in the total number planted, 

 but by considering the class of fish distributed, the difference is more than 

 compensated for, and this is shown by the following comparison : 



Speckled Trout Distribution 

 1928 vs. 1929 



Eyed Eggs Fry Fingerlings Yearlings Adults 



(1 inch to 4K inches) 



1928 60,000 475,000 1,134,600 200 



1929 30,000 1,105,750 28,860 2,572 



Furthermore, at the time of writing there is on hand at the Normandale 

 and Mount Pleasant hatcheries a stock of approximately 90,000 yearlings, which 

 is the product of fingerlings retained in rearing ponds from the spring of 1929. 

 Losses among these at the Mount Pleasant hatchery amounted to less than 

 one per cent, and at the Normandale Trout ponds the losses were insginificant. 



