VALUE OF NORWEGIAN LAKES FOR FISH CULTURE. 579 



eel goes from the fresh waters, where it has passed its preceding life, 

 down into the sea, as commonly supposed, to propagate its species, and 

 thereafter does not return to the fresh waters, but continues its life in 

 the sea, where it is thought to make regular journeys from place to 

 place. No one has ever come across adult eels migrating upwards from 

 the sea. What causes this wandering out to the sea no one knows. 

 The exodus includes both larger and smaller eels at the same time, 

 which do not appear to be of the same age or degree of maturity, and 

 so there are found simultaneously in the sea both small and large eels, 

 as in the fresh waters from which they descend. It is a warm- water fish, 

 and therefore is seldom found more than 500 feet above the sea-level, 

 but thrives in all kinds of waters, large and small, with or without afflu- 

 ents, if they only have a muddy bottom in which they can bury them- 

 selves in winter. 



It lives exclusive^ on animal food — insects, snails, fish, and flesh 

 of all kinds until and after it has become putrefied. It is easily 

 caught in many ways ; the easiest, however, appears to be unknown in 

 this country, at all events it is employed very rarely — namely, to cap- 

 ture it in so-called eel-traps in its migration towards the sea, which is 

 universal over all Sweden. 



It is considered by many a very well-flavored fish, and commands a 

 high price. It grows very quickly. While 1,800 young eels are required 

 to weigh a pound, one-half kilogram, onl}^ 30 yearling go to make up the 

 same weight. At the age of three or four years the eel reaches a 

 weight of one kilogram. One can cultivate it by collecting the young 

 during the migration from the sea, and therewith stocking ponds and 

 pools, and if one provides for a sux)ply of food, living or dead, they will 

 grow quickly. The mode of cultivation which, however, will jJresuma- 

 bly answer the purpose best will be to place the eels which are caught 

 in the river or the sea, fresh or salt, and which may not have reached a 

 suitable size, in a separate pond, and then to feed them well with all kinds 

 of ofifal of flesh and fish, to which there must be easy access ; if it is a 

 little putrefied it will, as remarked, do no harm. They will then grow 

 very quickly, and give a good return for their care and food. One must 

 in the mean time look out that they do not escape from the pond, by sur- 

 rounding them with an iuclosure which the eel cannot climb over or 

 creep through ; otberwise they will in the night, during a heavy dew or 

 rain, leave the pond aud disa[)pear. A belt of loose sand about the 

 pond will prevent them also from escaping, if it has sufficient breadth. A 

 pond for such purpose ought to have a muddy bottom and hollows in 

 the sides in which fish may conceal themselves and find shelter both 

 in warm aud cold weather; if one can conduct running water through 

 the pond, it will become so much the more profitable. In an extent of 

 twenty square meters 150 to 200 eels can be accommodated and thrive 

 well, if they simply obtain sufficient food. 



This fish is well adapted for stocking ice-ponds, which, because of a 



