THE CARP AND THE STICKLEBACK 



goes deeper into the real depth of the creature, and is 

 concerned with the number of spawnings in the same 

 individual, and, by extension, to the length of its life. 

 Unlike the carp, which spawns regularly once every 

 year for several consecutive years, the stickleback spawns 

 only once, or at most twice, in all its life. This spawning 

 takes place, according to locality or climatic conditions, 

 in the latter part of spring or the beginning of summer. 

 Usually, when it is accomplished, it exhausts the repro- 

 ductive capacity of the creature; it does not happen 

 again, at least in the majority of instances, and does not 

 recur the following spring. And there is a very definite 

 reason for this, which is that the completion of the 

 reproductive act marks the approaching end, the dis- 

 appearance of the individual. 



It is easy to see this when we fish for stickleback at 

 regular intervals throughout the course of the year. At 

 the beginning of spring, before the spawning, when the 

 water, newly warmed by the sun, indicates the end of 

 the winter's rest, all the sticklebacks we catch are of 

 average length or large size; all, or practically all, 

 are obviously adult and perfect animals. This is the 

 case also at the spawning period, but not afterwards. 

 During the latter part of summer, the fish we catch are 

 a mixture of large and very small sticklebacks, the latter 

 newly hatched from the eggs that have just been spawn- 

 ed, the former the adults which produced them. Then, 

 towards the end of summer, when autumn announces 

 itself by the first spells of cold weather, we find the 

 larger fish disappearing and a greater number of small 

 ones. When we compare the results obtained, we find 

 increasing development on the one hand, and decadence 

 on the other. Finally, as winter sets in, the large stickle- 

 backs, except for a few survivors, have ceased to exist ; 

 whereas the little ones, having passed through the stage 

 of youth, have become those we shall catch the following 

 spring, all ready to spawn when the weather begins to 

 get warm. 



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