PROPAGATION AND DISTRIBUTION OF FOOD FISHES, 1925 467 



extends from Rainy Lake, Minn., eastward to Lake Champlain, 

 and the commercially valuable fishes to which particular attention 

 is directed are the lake trout, whitefish, cisco, pike perch, and carp. 

 Owing to unfavorable weather in practically all fields during the 

 egg-collecting season, the output of these stations was considerably 

 smaller than in the preceding year, the largest decline being in the 

 case of the whitefish. 



DuLUTH (Minn.) Station 

 [S. p. Wires, Superintendent] 



During the early fall arrangements were made for the collection of lake-trout 

 eggs in Lakes Superior and Michigan. Small numbers were obtained daily at 

 Washington Harbor and at other points near Isle Royale, Mich., between Sep- 

 tember 28 and October 9, when the beginning of the closed season necessitated 

 discontinuing the work. It was resumed on October 15 and prosecuted to the 

 middle of November, but the results were small owing to bad weather and the 

 light run of fish in this region. Along the south shore of Lake Superior, where 

 spawning was most active from October 13 to the close of that month, there 

 was a good run of fish, and egg collections were correspondingly large. The eggs 

 secured from the 15 fields occupied aggregated 21,535,000. On reaching the 

 eyed stage 1,550,000 were shipped to applicants; fry and fingerling fish to the 

 number of 12,752,500 were produced from the remaining stock and distributed, 

 a large proportion being returned to the native spawning grounds. 



On account of almost constant stormy weather no nets were set for the capture 

 of whitefish on the natural spawning grounds at Munising, Mich., hence the 

 station's collections of eggs of that species were limited to the Isle Royale field, 

 where 1,560,000 were secured. As a result of operations in the vicinity of the 

 Bemidji State hatchery, conducted in conjunction with the Minnesota Game 

 and Fish Department, the station secured approximately 27,500,000 pike perch 

 eggs between April 17 and May 3. To avoid the heavy losses incident to handling 

 in the green state, the eggs were eyed at the point of collection and then trans- 

 ferred to Duluth. Managed in this way, the losses were kept at a minimum. 

 The resulting fry, amounting to 13,000,000, were delivered to applicants in 

 Minnesota, Michigan, and Wisconsin. The year's work also included the incu- 

 bation of 360,000 eyed brook-trout eggs received during the early winter from 

 commercial hatcheries in Massachusetts, Rhose Island, and Wisconsin, and 45,000 

 steelhead eggs transferred during the early part of May from the Clackamas 

 (Oreg.) station. 



NORTHVILLE (MiCH.) STATION AND SUBSTATIONS 

 [W. W. Thayer, Superintendent] 



The year's work at the Northville station consisted in the propagation of 

 smallmouth black bass, bluegill bream, brook trout, and rainbow trout, the eggs 

 of the two latter species being derived from outside sources. The smallmouth 

 bass fry on hand at the beginning of the year were reared and distributed as 

 fingerlings Nos. 2 and 3. On the last day of the following April, when the work 

 of apportioning adult bass in the station breeding ponds was undertaken, it was 

 discovered that some of the fish had spawned in their winter quarters, this fact 

 being disclosed by the presence of several nests containing dead eggs. It is 

 believed that this unusually early spawning was occasioned by the spell of unduly 

 warm weather which prevailed in the latter part of April, and that the eggs were 

 killed by a sudden lowering of the temperature which occurred shortly before 

 the ponds were drawn. 



In addition to the bass carried through the winter at the station, 196 adults 

 were furnished from the Put in Bay (Ohio) station about the middle of May, 

 this acquisition bringing the total to 325 iDrood fish. Spawning began in the 

 breeding ponds on May 10 in water of 58°. After rising to 60° on the 17th, the 

 temperature suddenly dropped to 52° on the 18th, but to all appearances the fry 

 were unharmed. Appro.ximately 200,000 fry of this species were hatched, of 

 which 94,000, in the fry and fingerling stages, were distributed before the close 

 of the year. 



During the early part of the winter of 1924-25 the station received 1,100,000 

 eyed brook-trout eggs, 500,000 of which were transferred from the Pleasant 

 Mount hatchery of the Pennsylvania Fish Commission. The balance consisted 



