280 KNUT DAHL. 



is so slow work, that I have not found time enough to enter 

 into this work. 



However one may with certainty start from the fact that 

 the young leaving the river during spring are at least IV4 years 

 old, because their hatching cannot have taken place later than 

 February— April of the previous year. 



Whether the young, which during summer continually 

 emigrate are the smallest of the young hatched in the previous 

 year or the largest of the fry of the year, I am not in a 

 position to determine with sufficient accuracy. In my opinion 

 it is not improbable that both annual classes are to be found 

 among them. 



This latter supposition does not seem to be confirmed by 

 the experience gained at the rearing establishments of our 

 government, where the fry from March to October only grow 

 from 2 to 8 cms (maximum) (Vide report of the inspector of 

 freshwater fisheries 1895—1896, pg. 14). 



However it would seem probable that the growth of the 

 fry in nature would be a good deal quicker than in hatching- 

 boxes, where thousands are penned together. Researches made 

 by P. P. C. Hoek (comparing the size of limited numbers of 

 artificially reared young salmon with those caught in the river 

 Prüm.) confirm this presumption. 



Also during the excursion to the Meldal, July 1901, I did 

 not succeed in observing (in the water) numbers of very small 

 young salmon, whereas the larger size of fry (parr) occurred 

 in countless numbers and could easily be caught and also ob- 

 served everywhere in the shallows and pools. The sizes are 

 denoted in the last column of Tab. IV. I regret to say that 

 this column does not correctly represent the lower size limit of 

 the fry, because I could with certainty discern young salmon 

 down to 5—6 cm. length rising in numbers to my flies, unable 

 to swallow them. It is quite certain, that the group in the last 

 column of the table would have included at least the 6 cm. 



