VALUE OF NORWEGIAN LAKES FOR FISH CULTURE. 591 



only a few lakes of any extent wliich are worth considering, that lie 

 higher than the stations where, for a long time, peojile have had dwell- 

 ings, and have thrived well. When, therefore, at some time the import- 

 ance of fish-cultnre has become recognized, it will certainly come to 

 pass that the necessary men for regular cultivation will remove to all 

 lakes of any importance in elevated districts, so that fish-culture, to the 

 extent previously supposed will be carried on, even up to the most ele- 

 vated lakes wliich maybe worth cultivating; because, even if hatching 

 cannot take place in the lakes themselves, there is nothing to prevent 

 obtaining satisfactory results by bringing to these lakes the required 

 stock of young from less elevated localities in which the hatching can 

 be done with greater ease. Such transportation will, as a rule, be an 

 easy and simple thing, since it will not be long, and, as a rule, can go on 

 in such a way that one, as often as he wishes, can look out for the most 

 thorough renewal of the quantity of water in the vessel in which the 

 transportation occurs. 



The next and most difiBcult question to answer is, how large a plant- 

 ing of fish may be considered proper under such a mode of cultivation 

 as previously provided ? With regard to this I shall next consider some 

 of the previously cited data. 



Mr. Seth Green states that two basins with an area, the uppermost of 

 22.5 and lowermost of 55.8 square meters, and with a capacity of 15.5 

 and 48 cubic meters, respectively, are sufiicient for 5,000 individuals of 

 one to two years old, and 2,000 individuals of two to three years old fish, 

 respectively, with a supply of water through both reservoirs, one after 

 the other, of 37.0 liters per second/ Since the trout, as a rule, stay on 

 the bottom, and only rarely distribute themselves at different heights 

 in the water, the spaciousness of the area is more to be considered than 

 its cubic contents. To each fish in these basins is thus allotted, respect- 

 ively, .0045 and .0111 square meter, and cubic space of, respectively, .005 

 and .024 cubic meter, with 5 and 24 liters of water. For each fish in 

 the first basin, there is also a surface of, for example, 15 centimeters 

 long, and 5 centimeters broad, while the fish at this age can have a 

 length of about 10 and a breadth of about 2 centimeters, more or less ; in 

 the other basin, each fish has a space of, for example, 20 centimeters in 

 length and 5.5 centimeters broad, and it will have a length of 15 centi- 

 meters, and a breadth of 3 centimeters or upwards. One perceives, also, 

 that fish can live and thrive in a very small space, if the water supply 

 and the food are sufficient. According to M. Bouchon Brandely's state- 

 ment, each four- year-old fish has .3 square meter ; it is, for instance, 75 

 centimeters long and 40 wide, and its size will be about 25 centimeters 

 long and 5 broad, while to each fish will be allotted a quantity of .3 cu- 

 bic meter, which equals 300 liters of water. The water supply he does 

 not mention. The relation concerning the surface and cubic room each 

 fish ought to have is thus, according to the two statements, considerably 

 different ; there can be no doubt that the larger it is the better. 



