28 



As an illustration of the size of tlie iumiigratiug glasseels, Tuble 5 gives 

 the measuremeuts of glasseels taken iu May and on Juue ]2th 190(j. Eveu so 

 late as this therefore, the immigration does not seem to have been coucluded at 

 Audebo in Lammefjord. The fresh water of Lammefjord Lake flows out here into 

 the fjord and forms at times a very strong current, in which \ve see that eels of 

 the O, I and Il-groups and somewhat larger are working their way up iu large 

 quantities. — It will be seen from the Table that the size of the glass-eels varies 

 somewhat at the dilferent piaces; at Audebo where the catch was made in the 

 middle of Juue, their length is obviously less than at the other two piaces; but 

 as the pigmentation was not greater in the specimens from Audebo, we cannot 

 directly compare this with the condition described by Johansen. 



After June 12th I have only once (on the 23rd of the same mouth) taken 

 and measured a large uumber of glasseels; it was iu a small brook at Frederiks- 

 havn. The pigmentation was perhaps somewhat more developed than in typical 

 glass eels and there were traces of iucipieut deposition of guauin crystals in the 

 peritoneum in some of them. Their size iu cm. is seen iu Table 6. Noue mea- 

 sured 73 mm. or above and a relatively large uumber was at ca. 65 mm. Thus 

 they were somewhat smaller than those abovementioned (Table 5). 



Table 6. 



Brook at Frederikshavn. 



fShiimp net with bobinet. 2ord June 1906. O ^ glass-eels. 



X = dark pigmented eels. 

 14 



13 X 

 12 X 



11 X X 



10 X 

 9 X X X 

 8 X X X X 



X X 



7 OOOOOOOOOOOOOOOOOOOO I , 



OOOOOOOOOOOOO ^ nniQDer 



.. ,.f. not measured. 



5 



Later in the summer I have taken and measured a few of the 0-group; 

 they always had the grouud-colour of the older eels, even on the belly, but could 

 however be distinguished from the next years's group by their small thiekness and, 

 from the middle of July on, likewise b}' the method of measuremeuts; see Table 7 

 (column 5 fig.), p. 29. Their growth in summer, which had not yet begun on 

 July Uth (Table 7), now proceeds quickly but is again (|uickly ended, so that on 

 the lOth and 23rd September we lind them at size 1—i)^,'., cm. with a very 

 distinctly marked maximum at 8 cm. Next spring, before growth again begins, 

 they have the same size (see Tab. 1 — 3), and their whole increase in growth 

 in the first year is thus ca. 1 cm. 



1. Gronp. 



Ou the Ist of May (date of arrival) the specimeus of this years group have 

 been 1 year in our waters. The majority measure 8 cm. iu leugth (see the previous 



