594 EEPORT OF COMMISSIONER OF FISH AND FISHERIES. 



abundauee of fisli "will thereby become too great, either -with regard to 

 the supply of food or of oxygen, it is an easy matter, by the assistance 

 of natural means or by the capture of a larger number of fish, to remedy 

 the difficulty. It will, probably, under all circumstances, be the best to 

 hatch out a greater quantity of eggs than is actually necessary, if there is 

 opportunity to retain them, and thereby gain experience as to the water's 

 nourishing capacity in both directions, because the larger the planting 

 which can be kept in good condition the greater the profit. To procure 

 10,500 impregnated eggs, are required female fish of a combined weight of 

 C to 7 kilograms, and a corresponding number of male fish, weighing 

 from 2 to 3 kilograms. This quantity of fish, with the appropriate mode 

 of proceeding, will be easy to procure in a not altogether fished-out lake 

 of the size mentioned, or even from far-distant lakes, in which case, how- 

 ever, it must be bought. After the expiration of the second year, at all 

 events, the lake will jield the desired quantity of eggs from the best de- 

 veloi)ed of the young first hatched. For the hatching of this quantity of 

 eggs, is required 3 to 4 square meters of space in a suitable apparatus. 

 Even if one, besides the fish which may be objects of culture, wishes to 

 hatch out some gwiniad, chiefly as food for the trout, and therefore in- 

 creases the size of the hatching ai^paratus to 5 square meters of surface, 

 the structure can only become inexpensive if no unnecessary luxury 

 is brought into use in a construction. In case of necessity the hatching 

 may occur in an open field. # 



Besides this hatching apparatus, as remarked, separate places must be 

 procured for the newly-hatched young. This will, as likewise previously 

 remarked, everywhere be an easy thing, by the construction of canals 

 or small ponds or damming up some little creek, which are arranged so 

 that they may be furnished with water from some brook or spring, or both 

 together. These ought to be prepared the year before they come into 

 use, so that they may be sufficiently stocked with water-insects, and 

 Crustacea. This requires only a few days' work and material of small 

 cost. 



The hatching of the kinds of fishes which may serve as food for the 

 cultivated fishes proper, and w^hich will thrive in a lake, is not difficult, 

 since it may take place in the lake itself with very simple and inex- 

 pensive apparatus, and in a very short time, since their spawning season 

 is short, and the eggs are hatched in a few days. The collecting of 

 the necessary quantity of eggs by the use of likewise very simple and 

 inexpensive arrangements is not at all difficult if the lake only contains 

 such fish. Xeither is the transportation from other lakes associated 

 with other difficulties than the transportation of trout eggs; it will 

 be necessary only a couple of times. Even if this may give rise to any 

 outlay, it will be just as well invested as the outlay for seed-corn for 

 fertile soil or the procuring of artificial manure for theland which needs it. 



In three hectares of water, should one, from the fifth year, harvest, on 

 the average, 2,500 adult fishes, of 1 kilogram each, or 2,500 kilograms. 



