Chapter X 



HIBERI'iATION 



"Hibernation", that is, the collectins of all stock fishes in small specially pre- 

 pared hibernating (winter) ponds, has a double purpose in carp culture: 



(1) to make possible the draiJiing of the extension and brood extending 

 ponds in the vdnter (on the sisnificance - see Chapter I, last paragraph 

 and Chapter VIII, E, ith paragraph), 



(2) To protect the fishes against dangers which threaten them in shallov; 

 ponds in winter. 



The winter dangers for the fishes, are that l]\e ponds sometimes freeze deeply, that 

 the fishes can be frozen in the ice, and above all tlie danger of oxj^gen shortage occurr- 

 ing after prolonged ice coverage. In many regions injuries by acid water occur particu- 

 larly in the winter. AH these dangers are naturally most easily banished if the fishes 

 are, gathered in one or in a few relatively smaller ponds. The continuous supervision 

 and the elimination of injuries is easiest there. 



However, it would be obviously false to combat the dangers mentioned and at the same 

 time perndt new dangers to the state of health to enter from the other side. Endangering 

 of the condition of health will absolutely set in if the fishes are too densely crowded, 

 s\iffer long starvation, become disquieted, and if the ponds do not show faultless, 

 completely unobjectionable hygienic conditions. 



I must for this reason designate the ever more freauently appearing custom of using 

 the hibernation ponds in the summer for extension and maturing ponds, as being a most 

 dangerous bad habit, which must lead in increasing measure to the infection of fish 

 stocks. Ir the silting up and neglect of the hibernation ponds I see one of the main 

 reasons for the spread of the contagious ascites disease (see Chapter XV) and many other 

 epidemics and diseases in the pond industries. 



The most important requirement for good hibernation is therefore: Complete draining 

 of the hibernation ponds during the entire summer, cultivation of the bottom surface if 

 necessary, thorough liming of the pond bottom in the spring after the fishing out, partic- 

 ularly of the muddy places. The bottom must in no case shov; mud in larger amounts. The 

 firmer and more loamy the soil is, the better is the hibernation of the fishes. The 

 bottom shouli not be strongly sloping on the entire surface, but as horizontal as possible, 

 in order to permit the fishes to rest upon a large area of the bottom. 



Ponis which are perhapc somev/hat small but well cared for, are better than large 

 muddy and reeded hibernating ponds. The hibernation of yearling carps was already dis* 

 cussed. I have emphasized there that a "letting stand" of the brood nursing ponds makes 

 possible the best hibernation for yearling carps. V.Tiere it cannot be carried out, the 

 yearling carps must at least be hibernated separately from the two year old carps and the 

 other fishes*. It is likevdse advisable to separate carps and tenches, in short a standard 

 fishery requires numerous hibernation ponds, at best a special pond for every kind of fish 

 and for every size class. 



In order to protect the hibernation ponis from complete freezing close dovm to the 

 ground, a water depth of 1.5 to 2.5 meters (5 to 8 ft.), and in the East a depth of 3 

 meters (9 ft. 10 in,) is necessary. In the East where the after winters almost everj' 

 year are ver;'- long, the hibernation of carps is particularly difficult. In East Prussia, 

 the beam structures erected according to the suggestions of Lietmanh have given good 

 results (see Fig. 60). 



In every square of horizontal beams is placed another cross of wire, so that ^ smaller 

 squares of about 1 square meter each, are formed. 



The horizontal beams of this pile foundation must be so fitted, that the ice freezes 



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