ANNUAL REPORT, 1940-41 23 



In all, twenty-one lakes were closed to fishing in 1940. These lakes will be 

 open in 1941. Raven, Head and Merchant lakes, which were closed in 1939 were open 

 in 1940. No creel census reports were received from Raven lake but the fishing in 

 both Head and Merchant showed the benefit of the year's respite. The availability 

 of lake trout in Head lake was almost twice as great in 1940 as in 1938. The situation 

 in Merchant lake is more complicated owing to the history of the fishery there but 

 there is no doubt that the fishing was substantially improved by closure. Owing 

 apparently to a slow growth rate, a single year's closure does not make a marked 

 change in the size composition of lake trout catches, but it does in the case of 

 speckled trout. Merchant lake which was famous for the size of its speckled trout 

 in the past, but which had more recently been disappointing in this respect, again 

 yielded some nice catches in 1940. The Ontario Fisheries Research Laboratory is 

 anxious to receive full reports of fishing in these lakes through the creel census 

 in order to assess the benefits of closure. 



It was not possible to carry on as extensive a creel census in 1940 as in previous 

 years. It is of interest to note that 1940 is the first year in which bass were reported 

 in any numbers from Happyisle lake, although they were known to occur there. This 

 rise of a bass population to a fishable level is a further and, it is to be hoped, a last 

 spread of this species in the Opeongo drainage. The creel census of lake Opeongo 

 has now been carried on for five years. The accumulated data have not only enabled 

 the investigators to follow the trend of the lake trout fishery there but are now also 

 sufficient to make a first approximation of the spawning escapement. It remains 

 to be seen whether the escapement in 1936 was sufficient to maintain the stock. An 

 answer to this should be found in the next two years when the young fish resulting 

 from the 1936 spawning will be entering the fishery. Enough creel census returns 

 for bass have now been received to make possible a classification of the bass fisheries 

 similar to that established for the lake trout. Bass lakes in which the average length 

 of the fish captured is between eleven and twelve inches produce the greatest 

 availability of these fish. Most of the creel census work was confined to Algonquin 

 South but records were also gathered for lake Traverse and vicinity. This is of 

 particular importance since lake Traverse is the only lake in the Park offering lunge 

 fishing. 



The investigations of the food habits of the game and forage fish were con- 

 tinued. The work on the food and growth of the yellow perch is almost completed. 

 The routine examination of the stomach contents of lake trout, speckled trout and 

 bass was continued at lake Opeongo. 



The study of the whitefish population in lake Opeongo was continued; there 

 are dwarf individuals which mature at two years as well as the more usual individuals 

 that grow to three pounds, or more, and mature at four years. 



Studies were made on the quantitative methods of sampling the plankton 

 population of certain lakes. Tests were made on the use of a smaller and more con- 

 venient form of the tube sampler which has proved to be more accurate than other 

 samplers currently in use. 



Stream studies, carried out from early May until mid-September were con- 

 cerned with the insect fauna and the speckled trout. Two locations were selected, 

 Mud creek, a tributary of the Madawaska river near the east gate of the Park, and 

 the rapids below Tea lake dam on the Oxtongue river. At the former location the 

 quantitative distribution of aquatic insects on different types of bottom and in 

 different reaches of the stream was studied. Changes in the fauna of a rapids flooded 

 out by a beaver pond last year were followed, showing some interesting results 

 which were reported at the meeting of the American Fisheries Society held at 



