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eel can therel'ore reckon upon rousiug great interest, not least iu this country, all 

 the more because trustworthy information on the matter is lacking. 



There is certainly no lack of views on this subject — but they must be 

 regarded as pure guesses and hardly rest upon actual observations. Thus 

 A. Feddersen in a little popular work (»Aalefaringeu«, Kjøbenhavn 1904) states 

 that it is generally considered, that the young eel one year af ter its arrival (the 

 elver he calls »aalefariug«) is 20 cm. loug (8 inches), without showing so far as can 

 be seen whether he shares this opinion, nor what reasons there are for it. In 

 the same work further, he writes that »the Swede Norbåck is of opinion that the 

 eel grows about 4 iuches in length each year; according to his view it is 6 — 8 

 inches long iu the first auturau, 12 — 14 inches in the second, 18 — 20iuthe third and at 

 this length weighs 1 — l^/o'^- A six year old eel is said to be 2 5 — 3 feet long, IV« — 2 

 inches thick and weighs 5 — 6 fT.« And Feddersen states that »the French pisci- 

 culturists have a slightly different scale for the growth: iu the second year ca. 

 14 — 15 inches and af ter the fourth year the eel is said not to grow.« He adds 

 however, that »these data do not suit all waters« and is of opinion »that the 

 growth of the elvers is naturally like that of other fishes, according to the nutri- 

 meut-qualities of the water in which they take up their abode to grow.« 



I have mentioned these extremely different data on the growth, in order 

 to show how contradietory they are and how little one really knows about the 

 question. It is obvious that the difficult path of observation has not been traver- 

 sed, nor have the necessary materials been collected nor the methods used which 

 are at our disposal for the determination of the age and growth of fishes. 



Even this side of the matter, to obtain the necessary material, i.e. a suffi- 

 cient number of specimens at all sizes, has its difficulty. It is naturally quite 

 easy to procure eels of the sizes the fishermen take in their nets and traps; but 

 special apparatus is necessar}' for the capture of all the undersized eels (those 

 that do not reach the smallest size permitted in Denmark: 11 inches to the root 

 of the tail = ca. 31.5 em. to the end of the caudal fin); a small meshed net is 

 the best for the capture of eels of ca. 20 — 30 cm., whilst the smaller under ca. 

 20 cm. can scarcely be takeu with any other apparatus than shrimp-uets, which 

 must be very fine-meshed or covered with bobinet-cloth ; as the latter does not 

 allow even the smallest to pass through. The shrimp shove-net can naturally 

 only be used in shallow water where one eau wade; but under favourable eondi- 

 tions (see later) it can take the small eels in quantities. It appears from the 

 methods of capture thus described, that it is difficult or impossible to procure a 

 sufficient number of eels of all sizes from the same place, so that it is not possible 

 to draw up a table showing all the yeargroups on the basis of material from a 

 single locality; to get a sufficient number of the eels ca. 20 — ca. 30 cm. is especially 

 difficult, as the tables show; comparatively few of this size are noted in them. 



If C. G. Joh. Petersen' s method by measurements were the only available 

 one for the determination of the growth and age of the eel, this circumstance 

 would have an unfortunate influence. However excellent the method may be for 

 the determination of the age of the small eels — and there it is quite indispens- 

 able — it cannot be used for the age-determination of eels over ca. 18—20 cm., 

 partly because of the difficulties of capture, partly because the larger eels cannot 



