478 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [12] 



The liumus coutained in tbese kinds of soil is dissolved and snpplies 

 food to the fish 5 it also favors the production and growth of many kinds 

 of plants, worms, and insects, all of which are excellent fish-food. The 

 above-mentioned kinds of soil combine two great advantages, viz., to 

 supply a sufficient quantity of suitable food, and to retain the water. 

 Clay soil, when containing sand, is likewise rich in food, and retains the 

 water, even during long periods of dry summer weather, and is there- 

 fore the best for "sky ponds." If the soil is loose, or even sandy or grav- 

 elly, the water soon percolates through it, and neither insects nor plants 

 can thrive, as the productive power of the soil is but small. It there- 

 fore affords but little food to the fish. Ponds having such bottom can 

 only be maintained as fish-ponds by a constant and superabuiidaut 

 supply of water from cultivated ground. 



But even as regards existing ponds the pond culturist should possess 

 an accurate knowledge of the quality of the soil of every pond [^ he 

 should therefore examine it carefully, for only thereby will he gain a 

 thorough knowledge of the exact condition of his ponds, enabling him 

 to make improvements wherever needed. An accurate knowledge of 

 the nature of the bottom of the ponds is as essential to the success of 

 the pond culturist as a knowledge of the soil and its different layers is 

 to the agriculturist. The examination of the bottom of a j)ond, as re- 

 gards the quantity of food-matter contained in it, will be easiest, and 

 lead to the most satisfactory results, just after the pond has been drained, 

 but not after it has lain entirely dry for some time, for it is of interest 

 to the pond culturist to know what plants and animals are contained in 

 the i>ond when it is full of water. If the pond has been dry for any 

 considerable length of time most of the plants and insects M^hich owe 

 their origin and life solely to the water have either disappeared en- 

 tirely or have decayed. After this first examination the soil of the pond 

 should again be examined after it has become entirely dry, so as to ob- 

 tain an exact knowledge of its component parts. Such an examination 

 slioukl, especially in large ponds, be made in a number of i)laces, for 

 the soil of a large extent of ground will vary considerably. 



If, after the pond has been drained, a great deal of mud is found at 

 the bottom, this is a sure indication of rich soil. In that case the bot- 

 tom is generally composed of clay or loam with a slight admixture of 

 sand, and the mud produced by the decay of the many products of this 

 rich soil, and partly introduced by rain or snow water, will directly 

 serve as food for fish, and also indirectly answer the same purpose by 

 becoming the abiding-place of many insects and plants wliieh fish eat. 

 The water of such ponds is generally muddy, and has a i ) row nish-y el- 

 low color. 



G. Protection against inundations.— If a neighborhood is ex- 

 posed to frequent inundations, special attention should be given to this 

 matter before the pond is laid out ; for if it is impossible to secure ponds 

 against such calamities, tlie entire fish harvest will frequently be lost. 



