658 KEPORT OF COMMISSIONER OF FISH AND FISHERIES. 



lower aquatic fauna, did not satisfy the proprietor. He was anxi- 

 ous to find if it would be possible to increase tlie fish-food by creat- 

 ing' still more favorable natural conditions. He therefore applied to 

 Prof. Dr. Gustav Jager, in Stuttgart, who several years ago had advo- 

 cated the construction of "gnat-ponds" as a great aid in raising young 

 trout. After having, personally examined the establishment in August, 

 1876, Dr. Jager drew up the plan for the feeding-ponds and for the " cham- 

 bers" for the young fry, as they are represented in our diagram. He 

 thought that it was not good to distribute the young fish immediately over 

 a large pond, as they escape observation ; in his opinion it would be far 

 better to place them first in a small pond, and then gradually into larger 

 ones. The fish should be within easy reach, so that their mode of life 

 could be controlled, and the so-called " gluttons," i.e., the stronger ones, 

 which use much of the food destined for the smaller ones, could be re- 

 moved. But, as in the small space they have less chance to find food, 

 it inust be introduced from outside; and to facilitate this process is the 

 object of the feeding-ponds (1-16); they are shallow ponds, with stagnat- 

 ing water, and full of aquatic plants. The feeding-ponds 6-16 receive 

 their water from the canal Z, which is connected with the pond # 2 . 

 Sluices regulate the admission of water ; subterranean wooden pipes 

 8'" square, which can be closed, make the connection with the " cham- 

 bers" for the young fish. From the canal Z a pipe going over the spawn- 

 ing-canal leads the water into a similar canal running alongside of 

 the feeding-ponds 1-5, which are arranged in the same way as 6-16. The 

 ditches leading to the pond Wa from 8 5 and Si are used as "chambers" 

 for the young fish. Wooden cross-walls with a wire grating divide 

 these ditches into smaller divisions, which are again subdivided into 

 two parts by a single board running lengthwise. All these separating 

 walls can be removed, and the compartments be made larger. Into 

 these " chambers" for young fish, the contents of the feeding-ponds can 

 be conducted by pipes. These feeding-ponds and "chambers" for the 

 young fish were constructed during my visit, aud will already come into 

 use after the hatching-period 1876-1877. The water coming from the 

 feeding-ponds must, of course, not rush into the "chambers" too vio- 

 lently, because this might kill the young fish. As long as ice forms, 

 they cannot be used, on account of their limited depth ; but as soon as 

 spring begins, they will, if the vegetation is luxuriant, and if the water 

 is stagnating, and can therefore be easily warmed, become a most suc- 

 cessful hatching-place for numberless lower aquatic animals. If even 

 the large ponds, by using a fine net, yielded in a very short time sufficient 

 food for thousands of young trout, it will be all the easier to obtain 

 such food with a fine net from smaller ponds, if the draining of the 

 ponds should not yield the desired result. JThe young trout and saibHng 

 are therefore rained in the Freiland establishment on exactly the same food 

 as they eat when in open waters ; but special arrangements have been made 

 to supply this food i)i unusually large quantities. 



