chemical characteristics of the Great Lakes. Our limnological research staff have 

 provided effective liaison with the Institute and the results of their program are 

 now readily available to our staff. The efficiency of both limnological and meteoro- 

 logical data collections, undertaken by each of our research units, has been, and is 

 being, improved by this research team. Special projects dealing with the apparent 

 rapid ageing of the Bay of Quinte, and with the fouling of commercial gill nets by 

 algae, have been initiated. 



PARASITOLOGY 



Studies of the parasites of Ontario fishes continued in 1963 with collections 

 from Lakes Ontario, Erie, Huron, Opeongo and Lake-of-the- Woods. Occasional 

 specimens were also submitted from many other waters throughout the province 

 by Departmental staff and by anglers. The number of "firsts" in this work, new 

 host species, new parasites, and new records continues to impress us with our 

 ignorance of this subject. Much has yet to be learned about the kinds of parasites 

 we have in our important fish species before we can move on to assessing their 

 effects and possibly to developing techniques for reducing the levels of parasitiza- 

 tion. It is considered quite possible that some of the parasites identified are capable 

 of causing fish mortalities of serious economic proportions in waters as large as 

 the Great Lakes. Some parasites, if obvious to the naked eye, reduce the market- 

 ability of commercial species. 



SELECTIVE BREEDING 



The selective breeding of hybrids between brook trout and lake trout has as 

 its objective the development of a new breed which, by virtue of spawning at an 

 early age and of being able to swim in deep water, will be able to maintain a 

 population in the former lake trout habitat of the Great Lakes, even if the control 

 of sea lampreys proves impractical. In addition to this immediate and practical 

 objective, much is also being learned about the patterns of character inheritance 

 in fish. Such new knowledge and techniques may well be as important in future 

 fisheries management as it now is in the fields of agriculture, livestock and horti- 

 culture. Problems of overcrowding and disease because of inadequate physical 

 facilties continued to plague the project during 1963. Some relief was provided by 

 the loan of space and facilities at the Tarentorus Trout Rearing Station at Sault 

 Ste. Marie. This space has allowed the mass selection work to resume after its 

 interruption during 1962 and the consequent discarding of a year class. 



The key to additional facilities for the project at Maple may have been 

 discovered during 1963 with the development of a filtering arrangement which 

 allows the re-circulation of water. If this equipment is workable on a large scale, 

 water supply limitations will have been circumvented, not only for this research, 

 but potentially for new production hatcheries throughout the province. 



Results of recent tests of the inheritance rate for the characters we are selecting 

 are such that we are almost positive that the project will be a complete success 

 within the next five years if the physical facilities to complete the work are made 

 available. 



LAKE PRODUCTIVITY 



Studies aimed at developing a system of classifying waters, based on their 

 potential to produce pounds of fish were initiated by the Fish and Wildlife Branch 

 some years ago. This work has been recently extended by staff of the Research 



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