14 THE SCIENTIFIC ANGLER. 



season ranges from March to November. The majority 

 of mature fish ascend and descend at fixed periods, the 

 time chosen generally being during a flood. The early 

 spring floods bring the first and mam instalments to the 

 sources of the rivers; but in the event of these failing, 

 the fish often prolong their stay in salt water bays and in 

 the mouths of rivers until the first rising of water will 

 admit of a passage. There are in most salmon rivers 

 numerous weirs so constructed as to render the passage 

 of fish an impossibility, except during a heavy flood. In 

 waters where these artificial obstructions do not exist, 

 migratory fish pass frequently to and fro, these periodic 

 ascents being doubtless occasioned by the quest of food. 

 For a salmon to remain in good condition for a pro- 

 tracted period in fresh water would appear to be an im- 

 possibility. Their ova are vivified and their young 

 flourish in the inland streams, but after attaining a given 

 size their growth stops, and they sicken and die if the 

 passage to salt water is obstructed. The cleansing in- 

 fluence of the marine trip is necessary at least every two 

 years, even when the supply of food in fresh water is am- 

 ple, which is seldom the case. The freshly run fish may 

 be said to be invariably fat, and in the best possible con- 

 dition, not only in the substance of the flesh, but in the 

 large quantities of adipose matter which is found on the 

 pyloric appendages, which secret store serves as an inter- 

 nal source of sustenance, supporting the fish during its 

 summer stay in fresh water, where food is comparatively 

 scarce. 



It is often asserted that anadromous fish will not feed 

 except in salt water, and that their internal fat sustains 

 them when absent from it. This is most certainly 

 erroneous, as migratory fish are not more given to fasting 

 than are any other fresh water species when food is plen- 

 tiful. The young of both grayling and trout suffer 

 greatly from the presence of salmon in the tributaries of 



