22 DEPARTMENT OF GAME AND FISHERIES No. 9 (1941) 



Maskinonge: 



The distribution of maskinonge fry was approximately 33.4 per cent greater than 

 that of the previous year. This was due to the successful operation of the new hatchery 

 located at the outlet of Deer Lake, vicinity of Havelock, Peterborough county. 



For the first time in the history of the Department, maskinonge fingerlings 

 (three to eight inches in length) were reared by the pond method. Although the num- 

 ber reared, namely 1,300, appears small, it should be remembered that this was an 

 initial trial, and gives promise of greater success in the future. 



Our previous experiments revealed that there were two important factors which 

 should not be overlooked in the culture of maskinonge, namely: 



(1) Providing a suitable and abundant food supply 



(2) Preventing cannibalism, which invariably occurs in the absence of pro- 

 tection or lack of proper food staples. 



A culture of Daphnia was introduced and the pond was fertilized with suitable 

 quantities of sheep manure and superphosphate throughout the season. A typical 

 maskinonge environment was simulated as closely as possible by planting aquatic 

 and semi-aquatic vegetation. Special efforts were made to provide as much leafy 

 vegetation as possible in order to protect the young maskinonge from each other and 

 from other predators. 



A small pond adjacent to the maskinonge pond was used for the culture of the 

 blackhead minnow. The progeny of this important forage fish was used as food for 

 the growing maskinonge throughout the season. It was found necessary to supplement 

 the food requirements with minnows harvested from natural waters. 



In addition to this experiment, an effort was made to determine the possibilities 

 of rearing maskinonge to fingerling sizes in a natural area. Dr. Paul F. Elson of the 

 Department of Biology, University of Toronto, undertook this particular phase of the 

 field work under the supervision of the Department. The area selected was a marshy 

 bay about ten acres in extent, located on Stony Lake in the vicinity of Burleigh Falls, 

 Peterborough county. The area was closed off from adjacent waters by barriers across 

 the two ends, which were respectively 50 feet and 150 feet wide. Screens 

 were placed in the barriers to allow circulation of water. The area is a natural 

 spawning ground for maskinonge and, hence, should be suitable for raising these 

 fish. The water throughout the area is from three to five feet deep; the bottom is 

 deep muck, permitting a rich growth of weeds. When the area was closed off, coarse 

 fish and other predators were netted out, sometime before and after the maskinonge 

 fry were planted. Altogether 17,883 coarse fish and 563 turtles were removed from the 

 area. Less than one-third of the coarse fish, and slightly over one-half of the turtles, 

 were removed previous to the planting of the maskinonge fry. On June 4th, 100,000 

 maskinonge fry, about three weeks old, and approximately five-eighths of an inch 

 long, were planted throughout the area in locations where natural food was most 

 abundant. At this time they were feeding on small aquatic animals, including water 

 fleas. These Crustacea were present in vast swarms near patches of cat-tail and 

 marsh grass. About mid-June the maskingonge commenced to feed on minnow fry, 

 which were abundant. Growth of the young maskinonge under natural conditions is 

 amazing, as is indicated by the following table: 



Date June 6 July 5 Aug. 1 Sept. 1 Oct. 1 Nov. 1 



Length of fish 



in inches %" 3"-5" 4"-7" 6"-8" 7"-9" 8"-lli^" 



Seventeen fish taken in November averaged between 9i^ to 10 inches in length. 

 The results of the first season's work may be summed up as follows: 



