18 



DEPARTMENT OF GAME AND FISHERIES 



No. 9 



WATER LEVELS: 



In view of the shallowness of the water in which maskinonge, pike, black bass 

 and forage fish spawn, sudden fluctuations in water levels over natural spawning 

 beds are inimical. The Department has appealed to all those responsible for such 

 operations and the Department of Railways and Canals was supplied with the follow- 

 ing data on the waters on which they operate dams for power and navigation pur- 

 poses, namely, the fish frequenting the waters, the spawning dates of the various 

 species and the spawning depths. As a result we look for definite improvement 

 along these lines. Judging from information received from our field oflacers, con- 

 siderable improvement is evident. 



NUTRITION OF TROUT: 



During the fall, winter and spring of 1935-36 a number of feeding experiments 

 were conducted in the Department's experimental hatchery in the Parliament 

 Buildings, Toronto. The object of these experiments was to find a suitable food or 

 mixture of foods that would produce healthy and vigorous trout at a lower cost 

 than the food generally used, namely beef liver. 



Previous investigations of this nature have been conducted by the Department 

 and a short account of this was given in a report of December 21, 193 5, entitled 

 'Ontario's Problems in Fisheries and Status of Research,' published in the proceed- 

 ings of the Conference on Fresh Water Fish Culture, Ottawa, January 3rd, 1936. 



The experimental hatchery contains four large glass aquaria 5' x 3' x 26" of 

 water; six galvanized iron troughs, 2'4" x 6" x 6" of water; and four troughs, 

 5' x IOV2" X 5" of water. (The small galvanized iron and wooden troughs were 

 painted on the inside with paraffin varnish). Thus the experiments were divided 

 into three groups and in each unit of each group, similar conditions prevailed. In 

 each group a control unit was set up in which beef liver was used as a standard 

 for comparison with the other feedings. Two per cent, by weight of cod-liver oil 

 was added to all feedings. The diets used are tabulated below, indicating any 

 changes made during the course of the experiments. 



The diets used in the experiment and the percentages of the various constit- 

 uents were as follows: 



