148 KENDALL: NEW ENGLAND SALMONS. 



upon the water. If they have the opportunity they will eat the eggs of other fishes. 

 They have been seen l>ang below the redds of brook trout and as the spawn was emitted 

 by the trout they would dash in and help themselves to the eggs. 



Spawning. 



The anadromous habit is not restricted to the sea salmon for the lake salmon also 

 usually ascends affluents of lakes to breed. But, curiously enough, in some instances, 

 it may be said to be catadromous in that it descends outlets. Facts and theories have been 

 advanced to explain the anadromy of the sea salmon. Some of these have been pre- 

 viously discussed in this memoir. It is difficult to apply these beliefs to the lake salmon. 

 There are no spring and summer migrants of the lake salmon homologous to those 

 categories of the sea salmon, although the fish enter both inlets and outlets in the spring, 

 presumably to feed. The movement associated with the 'breeding impulse' occurs in 

 the fall, although it may begin a month or two before the spawning time. But the 

 requisite conditions for spawning are precisely the same as in the case of the sea salmon, 

 relatively cold-running water and a gravelly bottom. It may be imagined that the ad- 

 vanced development of the reproductive organs initiates the movement for reproduction, 

 and it is conceivable that the fish are so sensitive that they quickly detect the inflowing 

 or outflowing currents, with, perhaps, cooler water and increased content of dissolved 

 oxygen. It is noticeable, too, that in the stream which they ascend, the run is more 

 Ukely to occur after a rise of water foUowing a rain. How a rise in an effluent could 

 induce a downward migration is not quite so clear. However, it is possible that the 

 increased current of the outflow is felt in the lake. At Grand Lake Stream it has been 

 observed that salmon would Unger in deeper water until a gate in the dam was raised 

 sufficiently to cause a more rapid outflow, when they would come down close to the dam. 

 Thus by this means they are induced to enter the trap-net set to take them for propa- 

 gation. 



Of the 'SiKverlax' of Lake Wenern, 'Rudge' (1909, p. 378) says: 'About the middle of 

 May it begins to ascend the Klar Elv (and in smaUer numbers the Gullspangs Elv), 

 and continues to do so until the middle or end of July, the run being generally at its 

 height about Mid-summer Day. By the way of this stream and its continuation north- 

 wards, the TrysU river, it has reached Osterdal in Norway, where it is now found in 

 several lakes. In September and October it spawns, after which it returns to the Venern 

 remaining there throughout the winter.' 



Of the Lake St. John fish, Creighton (1892, p. 87) says: 'The rivers which flow into Lake 

 St. John all contain Wananishe, which, however, do not ascend them in any great 

 number tiU the autumn. The ova are weU developed at the end of September, and the 

 fish are then on their way to the spawning-beds, which are, as in the case of the salmon 

 proper, gravelly shaUows with a steady current over them. The spawning season is at 

 the end of October. The spring movement of the fish from Lake St. John down into 

 the Grande Decharge, and the autumn movement up into the rivers flowing into the 



