44 DEPARTMENT OF GAME AND FISHERIES No. 9 



of fish. In other words, the work of the Department's fisheries' laboratory is 

 more or less confined to the following studies: 



(1) Diagnosis, treatment and control of fish parasites and diseases. 



(2) Natural food of fish and the importance of the inter-relationships of 

 food-cycles and food-chains as regards the welfare of the fish. The significance 

 of food studies is a most important factor in connection with the methods of 

 planting both game and commercial species. 



(3) Nutrition and artificial feeding of hatchery reared fish. This subject 

 will be discussed under the title, "Fish Culture." 



Biological Surveys 



A matter of fundamental importance in any satisfactory programme which 

 has as its objective the rehabilitation of waters with suitable game, commercial 

 or forage fish is a close study of the stream or lake itself in order that suitable^ 

 accurate, and sufficient information may be obtained regarding the conditions 

 of life therein, such as quality of water, cover and food. These inquiries fall 

 into three main and characteristic groups: 



(a) Physical conditions of the water, for example, temperature, trans- 

 parency, colour, turbidity, permanency, depth and bottom. 



(6)*Chemical conditions of the water, for example, alkalinity, acidity, pH, 

 oxygen, carbon dioxide and hardness. 



(c) Biological conditions of the water, for example, plankton, bottom 

 fauna, fish and higher vegetation. All these factors after correlation act as 

 indices or criteria of the suitability of waters for diff^erent species of fish. In 

 other words they help to specify whether a lake or stream is suitable for trout; 

 trout and pickerel; bass; bass and pike; etc. 



There is another side to these studies, which is of primary importance and 

 that is by means of a study of the environment, the fish, and the fish food we 

 are in a position to state the type of environment that may best provide or be 

 expected to provide the necessary requirements for different sizes and ages of 

 fish distributed from our Provincial fish hatcheries and rearing stations. 



Studies of this nature are carried out, during the summer months when 

 growth and reproduction are at their height, when highest temperatures are 

 recorded, and when water-levels due to evaporation effects are lowest. The 

 investigations are carried out by university men who have a proper background 

 of information pertaining to the natural and physical sciences, and who have 

 received special training in fisheries studies as a result of laboratory or field 

 experience or both. The summer survey staff during 1931 numbered twenty- 

 one. Seven of these were undergraduates, two of whom had previous field 

 experience with the Department. All others engaged had university degrees 

 qualifying them for work of this nature. 



The personnel of the staff was as follows: 



Allmark, M. G., third year, Biology and Chemistr\', Queen's University, Kingston. 



Cameron, W. R., fourth year, Biology and Medicine, University of Toronto. 



Cook, W. W., M.A., Department of Biology, Queen's University, Kingston. 



Detwiler, J. D., Ph.D., Head of the Department of Applied Biology, University of Western 



Ontario, London. 

 Dibbon,W. L., B. A., Ontario College of Education (Graduate in Biolog>-), University of Toronto. 

 Dignan, H. J., B.A., High School Teacher, Port Hope (Graduate in Biologv'), University of 



Toronto. 

 Ebersole, E. O., doing M.A. work, Department of Biology, Queen's University, Kingston. 



*These conditions may embrace certain physical qualities also. 



