XXXII REPUHT OF THE COMMISSIONEE OF FISHERIES 



COMMERCIAL FISHES OF THE GREAT LAKES 



In securing eggs for stocking its Great Lakes hatcheries the bu- 

 reau is confined to collections made from ripe fish obtained in the 

 nets of the commercial fishermen, the spawn being taken by experi- 

 enced men sent out in the fishing boats. The degree of success at- 

 tained in this work is in the main d pendent upon the size of the 

 fishermen's catch, which is governed largely by prevailing weather 

 conditions. The species handled at these hatcheries are the lake 

 trout, whitefish, pike perch, cisco, and carp. A fairly successful 

 season was experienced in the work Avith the pike p 'rch, but with 

 this exception the egg collections of all species were smaller than 

 in the preceding year. Adverse weather was encountered in prac- 

 tically all the fields covered, especially in Lake Michigan during 

 the lake trout spawning s ason and in Lake Ontario while eggs of 

 the whitefish and cisco were being collected. 



MARINE SPECIES OF THE NORTH ATLANTIC 



The more important comme'i'cial species propagated at the coastal 

 hatcheries in New England are the cod, haddock, pollock, and winter 

 flounder. In the cod work at the Woods Hole (Mass.) station the 

 brood fish are purchased from fishermen in the fall months and held 

 in a specially prepared tank in the basement of the hatchery until 

 they have spawned. The eggs float with the current and are gath- 

 ered up in specially constructed boxes and installed in the hatchery 

 for incubation. During the fall and winter of 1924 the run of cod 

 at all points along the southern coast of Massachusetts was so light 

 that no brood fish were obtainable for the work at that station. Cod 

 were very plentiful in the vicinity of Gloucester, Mass., however, and 

 the eggs collected at the Gloucester hatcheiy were considerably in 

 excess of 1,000,000,000, being the greatest number it has ever taken. 

 The propagation of winter flounder was notably successful. The 

 southwestern coast of Maine was visited by a very heavy run of that 

 species, enabling the Boothbay Harbor station to secure a record col- 

 lection of eggs, the total for the season aggregating 2,027,901.000. 

 Very satisfactory results attended the efforts to salvage eggs of the 

 cod and haddock in the distant offshore fisheries. This work ex- 

 tended from the middle of February to early April, during which 

 period 137,355,000 eggs of the cod and 42,222,000 haddock eggs were 

 fertilized and planted on the spawning grounds from which the fish 

 were taken. 



i\riGRATORY FISHES OF ATLANTIC RIVERS 



The principal species in this group — the shad — is holding its own 

 in the Potomac Kiver with difficulty, and the protection it receives 

 during its short spawning season is inadequate. The state of the 

 weather has considerable influence on the run of shad. The most 

 suitable combination for enabling a large body of fish to reach the 

 spawning grounds appears to be a cold, backward spring, with floods 

 of cold water flowing from the principal rivers into the sea. Under 

 such conditions the fish apparently keep to the main channel or bed, 

 thus escaping many of the nets set on the shoals in the lower bays, 

 and large numbers ascend well above brackish water to their natural 

 spawning grounds in the streams. 



