676 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



therefore, consider the bastard of sibling and trout as the most suitable 

 fish for raising - iu ponds. 



Our beautiful aesche or grayling (Salmo thymallus) is unfortunately 

 not suited for raising in ponds, principally because it is confined to insect 

 food. This is all the more to be deplored, as this fish is particularly 

 sensitive to the impurities of the water. 



The huchen (Salmo hucho), on account of its great voracity and be- 

 cause it never eats anything that is dead, is only suited for raising in 

 ponds where there are large numbers of small and otherwise worthless 

 fish. 



The experiments in raising the finer species of Coregonus, e. g n the Core- 

 gonus mar ana and the Coregonus Wartmanni, in ponds are of too recent a 

 date to pronounce an opinion upon them. But so far these experiments 

 have been encouraging. 



The only salmonoid which has been raised in ponds for any length of 

 time is the trout. Thus the trout-ponds near the Wolfsbrunnen at 

 Heidelberg are widely known, as are also the trout-ponds of several fish 

 dealers, e. g., those of Peter Haenleiu, at Mombach, near Mayence, of Mr. 

 Leyfried, and Helmstatter Brothers, near Wiirzburg. 



Trout are not raised in any of these ponds, but merely fattened. The 

 dealers buy, often at a great distance, young trout measuring 5 to 6 

 inches in length, which have been caught in brooks, and place them in 

 their ponds. Here they are sorted according to years and fed with the 

 worthless cyprinoids which are caught in large numbers in the Neckar, 

 the Bhine, and the Main. In Heidelberg and Wiirzburg these food-fish 

 are generally placed in the ponds alive, but in Mayence they are only 

 put in dead. The former method of feeding is more convenient and may 

 especially be recommended in small ponds where the trout have not to 

 hunt far for their food. The method of feeding with dead fish adopted 

 in Mombach, near Mayence, is better calculated to fatten the trout. 



The food-fish are kept at Mayence in a live condition, and are every 

 day at a certain time taken to the neighboring village of Mombach, 

 where the trout get them dead but entirely fresh. Great care is taken 

 that the trout leave no remnants, and the excrements and scales of the 

 food-fish are carefully removed every day. 



In all the places which have been mentioned the quantity of spring 

 water used for feeding the ponds is comparatively small ; nowhere is it 

 more than can be conveyed by a pipe measuring about three and a 

 quarter inches in width. At the Wolfsbrunnen, near Heidelberg, the 

 quantity of water used for feeding the trout-ponds was larger, but since 

 most of the water is used by the city water- works, the ponds have to 

 manage with less water. 



In Wiirzburg and Mayence the trout-ponds are quite small, properly 

 speaking, only large tanks made of wood and cemented, which may be 

 laid dry and cleaned at any time. 



The Heidelberg ponds are much larger, and are, as far as I know, 



