85 



Fish Hatchery grew, under favorable cir- 

 cumstances, to a length of six inches in 

 one year. It must not be taken for grant- 

 ed, however, that trout six inches in 

 length are one year old. In their native 

 streams, in coder regions, they will not 

 often attain this length in two or more 

 years. 



In general we do not find large fishes in 

 small bodies of water ; neither do we find 

 the fish in our small aquaria growing at 

 an alarming rate. The fish disdains to 

 outgrow his surroundings ; he may feel 

 his importance, and consider himself in 

 many ways superior to the other fishes in 

 the pond with him, but he will not permit 

 himself to grow to such a size as to make 

 the question of securing a living a diffi- 

 cult or irksome one. 



Fishes spawn but once each year, and 

 the time and length of the spawning sea- 

 son is not the same for all species. With 

 some species the season is short, while 

 with others it may extend through three 

 or more months. In the latter case those 

 produced the first part of the spawning 

 season are at the end of six months much 

 larger than those which appear at the 

 close. It is therefore evident that the 

 fishes of any single brood by the end of 

 the year will vary greatly in size, often to 

 such an extent that the broods of one sea- 

 son cannot be separated from those of 

 the preceding season ; especially is this 

 true of our smaller species. Mr. Moenk- 

 haus, in making a study of the two spe- 

 cies of darters, the Sand Darter or "Joh"" 

 ny," and the Log Perch, found by col- 

 lecting a large, miscellaneous lot of these 

 fishes, from a given locality, that it was 

 possible to separate them in groups ac- 

 cording to size of one, two or three years 

 of age, which indicates a quite uniform 

 rate of growth for these two species. 



Mr. Voris collected a miscellaneous lot 

 of over five hundred specimens of the 

 Blunt-nosed Minnow from Turkey Lake 

 in Indiana, varymg trom one to three 

 inches in length. These, when separated 

 as far as possible, according to sizes, did 

 not fall into distinct groups of dififerent 

 ages. In my own collecting and study of 

 fresh water fishes I have always been im- 

 pressed with the difficulty of recognizing 

 the age of fishes, except that the smallest 



taken was considered to be the product 

 of the preceding spawning season. Here 

 is an interesting question to which but 

 little attention has been given. Any one 

 will find much interest in studying the 

 rate of growth of fishes under different 

 circumstances. We know that the rate 

 of growth is in no way uniform, as is the 

 case with our warm-blooded animals. We 

 also know that among fishes there is no 

 uniform adult size, as there is m case of 

 warm-blooded animals (birds and mam- 

 mals). In general, we cannot speak of a 

 fish as being full-grown ; at the same time 

 there seems to be a limit of size for each 

 species in each body of water, beyond 

 which only a few go. The Chinook sal- 

 mon we mentioned reach an average 

 weight of twenty to thirty pounds, al- 

 though individuals are occasionally taken 

 of forty, sixty or even one hundred 

 pounds weight. These large fishes are 

 by no means common, the other species 

 of salmon never attain the size of the 

 Chinook. 



There is an interesting family of fishes 

 in our fresh waters known as Minnows ; 

 these fishes are too small and too full of 

 bones to become a favorite for the table. 

 They are the most helpless of all our 

 fresh water fishes, being soft, and, as 

 they are slow swimmers, they become an 

 easy prey to larger fishes, and form a 

 large part of their food supply. They 

 have been constantly driven into smaller 

 streams and shallow water, until they have 

 become exceedingly dwarfed. Their only 

 use in the economy of fish life seems to 

 be to assimilate small organisms, convert- 

 ino- them into such shape that they can 

 be^taken by the larger fishes. Now the 

 Minnows of all the United States east of 

 the Rockies are small and, except m case 

 of a few species, they are less than six 

 inches in length. The predatory fishes, 

 such as the Sunfishes and Perches, Pike 

 and Pickerel, are their worst enemies, in 

 the Rocky Mountains there are none of 

 these fishes, and many minnows there 

 grow to a length of two feet or more, i he 

 only enemy of importance they have is the 

 trout but the minnow finds a more con- 

 o-enia'l climate in the larger bodies of 

 water, too warm for the trout. The strug- 

 gle for existence has been a severe one, 



