FISHERIES, GAME AND FORESTS. 223 



probably not only for concealment, but also to avoid the bright sunlight, which soonei 

 or later causes them to go blind, as it does many fishes when they have to live in 

 waters without shade. Toward the end of the spawning season, it is very common to 

 see blind lampreys clinging helplessly to any rocks on the bottom, quite unable to 

 again find spawning beds. However, at such times they are generally spent, and 

 merely awaiting the inevitable end. 



As with the Brook Lamprey, the time of spawning and duration of the nesting 

 period depend upon the temperature of the water, as does also the duration of the 

 period of hatching or development of the embryo. They first run up stream when the 

 water reaches a temperature of forty-five or forty-eight degrees Fahrenheit, and 

 commence spawning at about fifty degrees. Note, in the following table, how a rise 

 in temperature is accompanied by an increase of the numbers migrating during the 

 early part of the season. A temperature of sixty degrees finds the spawning process in 

 its height, and at seventy degrees it is fairly completed. It is thus that the rapidity 

 with which the water becomes heated generally determines the length of time the 

 lampreys remain in the stream. This may continue later in the season for those that 

 run later, but usually it is about a month or six weeks from the time the first of this 

 species is seen on a spawning nest until the last is gone. 



Wl)at becomes of Tl)em After Spawning ! 



There has been much conjecture as to the final end of the lampreys, some writers 

 contending that they die after spawning, others that they return to deep water and 

 recuperate ; and yet others compromise these two widely divergent views by saying 

 that some die and others do not. The fact is that the spawning process completely 

 wears out the lampreys, and leaves them in a physical condition from which they 

 could never recover. They become stone blind; the alimentary canal suffers complete 

 atrophy ; their flesh becomes very green, from the katabolic products, which find the 

 natural outlet occluded ; they lose their rich yellow color and plump, symmetrical 

 appearance ; their skin becomes torn, scratched and worn off in many places, so that 

 they are covered with sores, and they become covered with a parasitic or sarcophytic 

 fungus, which forms a dense mat over almost their entire bodies, and they are so 

 completely debilitated and worn out that recovery is entirely out of the question. 

 What is more is that the most careful microscopical examinations of ovaries and testes 

 have failed to reveal any evidence of any new gonads or reproductive bodies. This is 

 proof that reproduction could not again ensue without a practical rebuilding of the 

 animals, even though they should regain their vitality. A. Mueller, in 1865, showed 

 that all the ova in the lamprey were of the same size, and that after spawning no small 



