Insects, etc., of Caledonia Creek. 89 



board writes : " It is a well-known fact among fish-culturists, that the growth, 

 flavor and color of trout are largely affected by the food which they obtain. 

 To merely state the two extremes, trout fattened for market on liver are almost 

 worthless for the table, while those that visit the salt water, and obtain shrimp 

 and other similar food, are nearly equal to salmon." 



Visitors to the State Hatching-house, at Caledonia, who happen to be ignorant 

 or forgetful of this close connection between food and quality, as they make the 

 tour of the grounds, and feast their eyes upon the rare sight presented in the 

 thirty spacious preserves, each swarming with its hundreds or thousands of 

 brook trout, California salmon and salmon trout (some of the last, two feet in 

 length and ten pounds in weight), would naturally picture the table of those 

 engaged in the culture and care of those creatures as constantly supplied from 

 so desirable and convenient a source. They are surprised to learn that none of 

 these fish are ever placed upon the table, the flavor of their flesh being but a 

 few degrees removed from that of the liver on which they are fed. 



In reference to the influence of the food of fishes upon their color, Mr. 

 Charles Lanman states : " One principal cause for the great variety in the color 

 of the brook trout, is the difference of food ; such as live upon fresh-water 

 shrimps and other Crustacea are the brightest ; those which feed upon May-flies 

 and other common aquatic insects are the next ; and those which feed upon 

 worms are the dullest of all. * * * # Trout that frequent clear and cold 

 waters, and feed much on larvae [Phryganid] and their cases, are not only red 

 in flesh, but they become golden in hue, and the red spots increase and out- 

 number the black ones. * * * # The peculiarity of feeding on shell-fish 

 produced the gillaroo trout, a remarkable variety, found only in the Irish lakes." 



According to a statement of Professor Agassiz, " the most beautiful salmon 

 trout are found in waters which abound in Crustacea, direct experiments having 

 shown that the intensity of the red colors of their flesh depends upon the quan- 

 tity of Gammaridce which they have devoured. 



The improvement capable of being made to the natural flavor of fish seems 

 to have been known to the Romans, for it is said of them : " The art of breed- 

 ing and fattening fish was well known to the luxurious Romans, and many 

 stories are related about the fanciful flavors which were imparted to such pet 

 fishes as were chosen for the sumptuous banquets of Lucullus, Sergius Grata, 

 and others." 



The fondness and even preference, shown by many of our fishes for crusta- 

 cean food, is well established. Prof. Verrill, in his Report upon the Inverte- 

 brate Animals of Vineyard Sound* says : " These small Crustacea [Amphi- 

 pods] are of great importance in connection with our fisheries, for we have 

 found that they, together with the shrimps, constitute a very large part of the 

 food of our more valuable, edible fishes, both of fresh and salt waters. * * * * 

 Even the smallest of them are by no means despised or overlooked, even by 

 large and powerful fishes, that could easily capture larger game. Even the 

 voracious blue-fish will feed upon these small crustaceans, where they can be 

 easily obtained, even when menhaden and other fishes are plenty in the same 

 locality. They are also the favorite food of trout, lake white-fish, shad, etc." 



Crustaceans constitute almost the entire food of the herring (Clupea species), 

 a fish which, from its number and large consumption, is of so much value in the 

 fisheries of both hemispheres. According to a theory recently advanced by 

 Sars, the migrations of the herring, for a long time unexplained, are controlled 

 by the presence of their crustacean food. He affirms that a rich summer her- 

 ring fishery depends exclusively on the accidental occurrence of small crusta- 



*U. S. Commission of Fish and Fisheries, lleport for 1871-72, pp. 295-778, plates 38. 



