HAACK RAISING SALMONOIDS IN INCLOSED WATERS. 677 



only cleaned once a year, late in autumn. Special care is taken to re- 

 move the leaves which during summer and autumn are blown into the 

 ponds. These leaves thoroughly soaked with water sink to the bottom 

 of the pond and form the principal breeding place of the hurtful small 

 leeches, which, if once settled in a pond, can scarcely be exterminated. 



A fish-dealer in Frankfort-on-the-Main fattens the trout in a still simpler 

 manner. As there is not sufficient spring- water in Frankfort for feed- 

 ing the trout-ponds, Schauermann Brothers, of that city, have large 

 floating boxes in the Main, which are used as trout-ponds. In autumn, 

 when the water of the Main has sufficiently cooled off, medium sized 

 trout caught in brooks are placed in these boxes and are amply fed with 

 live fish. The trout can, of course, only remain in these boxes till the 

 beginning of summer, but by that time their weight has been doubled 

 or trebled. 



The most interesting method of fattening fish is undoubtedly that of 

 Mr. Kuffer, superintendent of the royal fisheries at Munich. It is 

 really a pleasure to see how this Nestor of pisciculturists manages his 

 establishment. Partly in small stone troughs and partly in small ponds 

 trout may be seen by the hundred weight, not only alongside of each 

 other, but in a literal sense above each other. In some of the stone 

 troughs there are certainly more trout than water ; but not only trout, 

 but the magnificent saibling of the Schlier Lake, large Sal/mo hucho, 

 enormous numbers of splendid eels from Italy, and, above everything 

 else, hundreds of thousands of the finest crawfish are here gathered 

 within a narrow space and enjoy the most careful treatment. 



Mr. Kuffer's establishment is highly favored by its natural location 

 and by the peculiarity of the Munich fish-trade. Powerful springs rise 

 from the two so-called "ports" in the almost perpendicular wall of rocks 

 forming one side of the court-yard. Summer and winter these springs 

 flow from the rock with the same strength, the same temperature, and 

 with ever clear and sparkling water; and thus it becomes possible to 

 keep such large numbers of trout and other fish within .such a small 

 space. 



In one court water from the river Isar can be brought in for the spec- 

 ial benefit of the cyprinoids ; and the experience of many years has 

 convinced Mr. Kuffer that this mixed water is absolutely necessary to 

 acclimatize the saibling which have been imported from the Schlier Lake. 

 If these fish were immediately put into pure spring-water they would 

 soon suffer from the byssus and would die. 



The peculiarity of tbe Munich fish-trade greatly favors this method 

 of keeping fish, as nearly every one buys his fish after the scales have 

 been taken off and after they have been cleaned. In this manner Mr. 

 Kuffer obtains a great quantity of entrails, and especially roe, of which 

 all fish are very fond. 



The trout and the Salmo hucho are not only fed with fish-entrails, &c, 

 but also with live cyprinoids. It is very interesting to observe the great 



