27 



O-group out iu tlie open liad assumed all tlie a|)pearauce of the eel. A single 

 specimen lived till oue of the last days io October and was then still distinctly a 

 »glass-eel«. 



How large are the elvers wheu they conie to our coasts? And 

 what is their growtli during the first year they live there? 



On these points we have the detailed investigations of A. C. Johansen (iu 

 the paper already cited), who coraes to the followiug result: »the glass eels wliich 

 appear in our waters and run up the water-eourses in spring (March — April), have 

 an average length of 70 — 72 mm. In June the majority have become pigmented, 

 and the average length is now reduced to 65 — 68 mm. Later in the summer they 

 again begin to grow in length, but the growth is so slow that their average length 

 in the next spring is only ca. 80 mm.« Johansen also gives tables of measure- 

 ments which show that the glasseels actually decrease in size, after they have 

 arrived in our waters. — This peculiar condition has now become more compre- 

 hensible, when it is takeu in conjunction with the great transformation undergone 

 by the eel in its larval stage, during which a cousiderable reduction in size occurs. 

 It is thus — as Joh. Schmidt points out in his paper already mentioned — the 

 last stage of this metamorphosis, which is passed here in our fresh water or at 

 our coasts. 



Table 5. 



Mouth of Tang River. 



Great Belt, Ttli May 1906. 

 Slirimp nut \\'ith hol)iiiet. 



Ribe River. 



2Sth M:iy 1906. 

 Shrimp net with bobinet. 



6 



G 



10 



13 



13 



23 



9 



6 



7 



3 



9 



Audebo. Lamme Fjord. 



12tli June 1906. 

 Shrimp net with bobinet. 



O 



15 

 15 

 18 

 37 

 23 

 30 

 27 

 16 

 20 



4 

 10 



6 



