phication of the lakes and ponds to the size, soil types, 

 physiography and other features of their watersheds are 

 showing promise. 



SELECTIVE BREEDING UNIT 

 The broad objective is to explore the potential of selective 

 breeding, hybridization and genetic manipulation as a 

 means of improving the quality of fish shocks or of modify- 

 ing species characteristics to accommodate environmental 

 changes. 



A serious loss occurred to the program when the entire 

 stock of 305, age III parent hybrid splake was stolen or 

 destroyed by vandals at one of our hatcheries. An additional 

 253 highly selected mature hybrids were stolen from another 

 hatchery. 



In April, 1970, 25,000 F4 fingerling splake from selected 

 parental stock were provided to the State of Michigan 

 where they will be reared to yearling stage before being 

 released in United States waters of Lake Huron. The same 

 number were transferred to the Chatsworth Hatchery from 

 where they will be transferred to our Lake Huron waters. 



The first major plantings of progeny from the Ontario 

 brood stock were made this year. They consisted of 100,000 

 yearlings in Lake Huron, 100,000 in Georgian Bay, and 60,000 

 in South Bay. 



Studies of the life history and ecology of successive gen- 

 erations of splake in natural conditions have been under- 

 taken as a means of learning what to expect of their 

 performance. 



Early maturing hybrids which are rejected in the process 

 of selection for deep swimming may have their own spe- 

 cific value. Although no better in their ability to perform in 

 shallow water than brook trout, they do have hybrid vigour. 

 Their performance is being tested in ponds as a basis for 

 comparison with brook trout and rainbow trout. Such a 

 study may suggest different selection procedures useful for 

 such waters. 



PARASITOLOGY UNIT 



The survey of the parasite fauna of fish in Lakes Erie and 

 Ontario was completed. A comparable survey of Lake 

 Superior fish was initiated. 



Considerable attention has been given to the develop- 

 ment of co-operative studies on parasites of particular im- 

 portance by individuals at the LJniversities of Toronto and 

 Guelph. 



A diagnostic service is provided to field offices, scientists 

 in other agencies, and to the general public, for the identifi- 

 cation of parasites, diseases and abnormalities. 



PRODUCTIVITY UNIT 



The broad objectives of lake classification are to provide a 

 means of estimating the effects of environmental variables 

 on yield of fish. A morphoedaphic index (total dissolved 

 solids divided by mean depth) has been useful for this pur- 

 pose and is being refined. 



TECHNICAL STUDIES 



A commitment was made in co-operation with Fish and 

 Wildlife Branch to assess plankton populations in Lake Erie 

 adjacent to the site of the Nanticoke Hydro development. 



CO-OPERATIVE RESEARCH 



Research projects, in co-operation with the Universities of 

 Toronto, Guelph, York, Ottawa, Montreal, Waterloo and 

 Dalhousie, Ontario Water Resources Commission, Canada 

 Centre for Inland Waters, Atomic Energy of Canada, 

 National Science Foundation, Macinnis Foundation, Royal 

 Ontario Museum, and Ontario Department of Agriculture 

 and Food, were carried out. 



FORESTRY SECTION 



The work of the Nursery and Plantation Unit was divided, 

 with tree production and field planting studies being trans- 

 ferred to Midhurst Nursery, and frost hardiness and dor- 

 mancy studies continuing at Maple as the Environmental 

 Physiology Unit. 



MAPLE UNITS 



SITE UNIT 



The present research program is not only oriented towards 

 land classification, which deals with the relatively stable 

 site features as a basis for assessing potential productivity, 

 but it is also aimed at serving silviculture directly by dealing 

 with the more variable site conditions and related actual 

 productivity. 



The acquisition of an atomic absorption spectrophoto- 

 meter, and improvement of other laboratory facilities, now 

 allows expanded co-operation beyond other forestry re- 

 search units to include fisheries and wildlife research pro- 

 grams requiring analyses for metal elements including 

 mercury. 



A study of the natural processes and relationships which 

 influence fertility is underway. 



Selection of suitable areas for studies, relating to the 

 inter-provincial fertilization program, continued. 



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