Stocking was done In some areas with lake trout which had been hatchery- 

 reared, and It was found that the commercial catch of this species was almost 

 entirely from this stocking. Some fishing effort was actually directed to catching 

 the planted fish, and the purpose of the stocking program may be defeated as the 

 trout had not reached reproductive maturity. Some method of curtailing this ex- 

 ploitation may have to be found If this trend continues. 



Studies of yellow pickerel In the Bay of Qulnte were again hampered by 

 staff shortage. Work on eels, white perch and sea lamprey predatlon was continued. 



Game Fish Studies 



Plantings of hatchery- reared lake trout continued to yield very poor 

 returns to the angler In Opeongo and other Algonquin Park lakes. This has led to 

 an Intensification of experimental work designed to understand why plantings here 

 fall while those In some other areas, such as South Bay, are successful. The role 

 of hard versus soft water rearing Is being assessed In this regard. 



Further attention Is being given to the differences between plankton 

 feeding as opposed to fish- feeding lake trout. It appears that the plankton 

 feeders, although smaller In size, are able to maintain catchable populations more 

 consistently than the fish- feeding trout. 



The long term study of the food habits of lake trout In Opeongo has 

 shown that with the decline of perch and the successful Introduction of clsco, and 

 with the consequent change of diet by lake trout, the average trout size has In- 

 creased almost 40 per cent. 



The final assessment of the effect of alternate year closure on lake 

 trout year class strength has shown no measurable benefit. A new closure regime 

 designed to produce strong year classes Is being considered. 



Smallmouth bass studies received full time attention from one scientist 

 during 1960 for the first time. This allowed analysis of the Opeongo bass census 

 data which Indicated a decrease In the average size of bass taken by anglers since 

 the size limit was removed, and an Increase In the total catch. 



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