COUNCIL — SEPT. 1912 — APPENDIX K — 132 — 



to check the decrease in value of the yield, which is to be feared unless special 

 preventive measures are taken. 



Considerable attention has for some time past been devoted to the question 

 of the improvement of the eel fishery, by means of eel fry set out in lakes, rivers 

 and ponds, as well as by precautionary measures calculated to assist and protect 

 the young fish against such obstacles as those caused by dams, waterfalls, etc. 



The fish used for stocking purposes are partly the little "glass eels" (Montée, 

 Aalbrut, Elvers), partly the somewhat older and larger „Satzaale" (Aalsetzlinge). 

 Our biological knowledge as to these younger stages has of late years been con- 

 siderably increased. The same may be said as to the older fish, especially with 

 regard to their age and growth and the proportional numbers of male and female 

 at different places (in fresh and brackish water, in the eastern and western Baltic). 

 There is still, however, an enormous amount of work yet to be done in this field. 

 The investigations must be carried out in a thoroughly systematic way, in order 

 that the results thereby attained may serve as a sure guide in determining the 

 measures to be taken for the improvement of the eel fishery. 



Also with regard to the more practical sides of the question, viz: capture 

 and transportation of eel fry, enormous progress has been made during the last 

 few years. A great number of works have been published from time to time, of 

 practical as well as of purely scientific nature. Among those whose researches in 

 this respect have been particularly successful must be mentioned: Bellini, Collett, 

 Drösgher, Ehrenbaum, Feddersen, Gemzöe, Gilson, Haack, Hein, Henking, fiERMEs, 

 HbEK, Hofer, Holt, Johansen, Leth, Lübbert, Nordqüist, Orsenigo, C. G. J. Peter- 

 sen, Redeke, Sandman, Schiemenz, Schmidt, Schneider, Seligo, Trtbom, Walter, 

 Williamson. 



Many of the questions here mentioned referring to the eel could, if not 

 already solved, be determined with comparative ease in the near future. 



As regards the laying down of eel fry (elvers or the somewhat older stages 

 („Satzaale")) the question arises, how to obtain the best results in point of growth 

 within the shortest space of time. This is one of the most important questions, 

 the solution of which of course demands a consideration of all the various factors 

 which bear on the problem. 



Taking as a starting point the expense incurred at a given place in connec- 

 tion with the laying down of a given quantity of eel fry, whether smaller or larger 

 specimens, it will be necessary to discover under what conditions the greatest total 

 increase is obtained within a certain area in a given space of time, whether artificial 

 feeding is used or not. It will of course be necessary for the purposes of investiga- 



