[85] * POND CULTURE. r,-,! 



It will 1)0 us impossible with the, raisin^' ponds as with the spawniiiji; 

 jxnids to lay down dolinitc rules as to tlie nuiuber of (ish to be jjlaced 

 in tliem, and experieiUH} will jnovc the best j^uide in this respect. As 

 a general rule one counts per hectare, in good raisinj;' ponds of the lirst 

 class, GOO fry; in niediuin, 450; in i)Oor, 300; in good raising ponds of 

 the second class, 400 two-year-old lisli ; in medium, 300; in poor^ L'OO. 

 liegard should also be had to the weight of the lish, as even lish of th(^ 

 same age will but rarely have the same size and weight; for. apart from 

 the inliueiice of the varying nature of the ponds, fish, like plants, will not 

 always thrive ecpially well if placed under the same conditions. If the 

 ])onds, however, have been carefully selected, this ditierence Avill make 

 itself felt but slightly. 



llorak* counts the following mimber of fry i)er hectare : In ^•ery good 

 raising ponds, 622 to 833; in good, 519 to 022 ; in medium, 41(1 to 529; 

 in poor, 210 to 313; in very poor, 103 to 154. Von Reider t places in 

 jjonds, which in case of necessity can be used as stock ponds, 1,500 to 

 3,000 per hectare, and in poor raising ponds only half that number; 

 and Teichmann,! in medium ponds, 2,350 to 2,830 per hectare. Kei- 

 mann§ says : "If a j)ond does not contain much food, I ])lace in it 1,880 

 young fry per hectare ; if it contains a medium quantity of food, 2,.'?50; 

 and if an abundance of food, 2,820." 



AVe here miss the data as to the age of the hsh, but considering the 

 high figures, there is no doubt that young fry, or one-year-old tish, 

 are meant. But even for young fry these are very high figures, and 

 it may be stated as a fact that all the above-mentioned pond cultiva- 

 tors have, as a rule, raised marketable fish during a one year's course 

 in the stock ponds. From this it may be inferred that in giving the 

 above data they had no reference whatever to poor ponds, liaising 

 ])onds which have been sowed the year before can stand a comparatively 

 larger number of fish than those where this is not the case. V,y ar- 

 ranging it so that every raising pond is sowed once in six years, the 

 growth of the fish will be furthered considerably, and the main object, 

 viz., to fit the young fish in the shortest possible time for the stock 

 ponds, will be attained. If possible, the raising ponds should lie dry 

 at least during winter. It is not always possible, however, to intro- 

 duce a regular system of rotation in sowing the ponds or to let tlic 

 l)onds lie during the winter, for sheer necessity will compel many a 

 pond cultivator to select for raising ponds ponds which consist of marshes 

 ami peat-bogs, and can, therefore, never be laid entiiely dry, or which 

 are used for industrial purposes, mills, &c., and can, for that reason. 

 never be drained entirely. A system of rotation in sowing the; ponds 

 can only be introduced on pond farms which possess a very laigc iiniii- 

 ber of ponds. 



* Horak, Teichwirthschaft, 1869. 

 + Von Reider, T^ns GrtHcc rfcr .F/.scAcrei, 1825. 

 i Teichmiinii, TcicUJlxchcrci, Leipzi}^, 18:'.l. 

 JReiiuann, rraktischer Abriss dcr Fitahcrci, 1^01. 



