ATLANTIC SALMON IN FRESH WATER 



By Charles G. Atkins 



In the fish-cultural work of the Craig Brook station the 

 Atlantic salmon has always been the leading species; and 

 the methods adopted, which have been essentially different 

 from those pursued with any species of salmon elsewhere, 

 have afforded data for some interesting and important bio- 

 logical deductions. 



The methods pursued are in outline as follows : Brood 

 fish are secured each year by purchase from the weir fisher- 

 men located on the tidal portions of the Penobscot River 

 and are conveyed immediately to a roomy enclosure in a 

 small fresh-water stream. Here they remain without food 

 and without other care than such as is necessary to guard 

 them against escape from the enclosure or destruction by 

 human or other foes, until late in the month of October, 

 when the earliest of their eggs are mature. Artificial work, 

 after the usual methods, relieves them of their eggs. Spawn- 

 ing is nearly always completed before the middle of No- 

 vember, and then the salmon are liberated — commonly in 

 tidal waters. 



The collection of brood fish is always made in May and 

 June, and at that early date it is found that the external ap- 

 pearance of the two sexes is so closely alike that it is impos- 

 sible to distinguish males from females, and they are there- 

 fore bought indiscriminately. In September, however, it is 

 found that the sexes have developed peculiar features which 

 afford ready distinction between the sexes. At the spawning 

 season it is always found that there are more females in the 

 enclosure, an extreme instance being the brood of 1910, 

 when out of 693 salmon there were 436 females and 257 

 males. In some other countries it has been reported that 

 there is a predominance of males. 



Early in the history of the station, studies were made on 

 the question of the survival of the salmon that had spawned 



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