30 



columus 3 aDcl 4, and compare with Table 2, coknmis 2 and 3. — It will scarcely 

 be clear from the tables alone, that the upper limit of this group in autumn must 

 be put at ca. 17 cm.; the direct evideuce of tliis will be given in describing the 

 uext group, and I may refer at the same time to what I have said on p. 24 

 concerning the »scale-limit«. 



A very large number of this group was taken in the course of the sum- 

 mer with the bobinet shrimp net. The fishing grounds were almost always ou the 

 margin of rotting Zostera, which is so often found washed up on the beach and 

 lies half on land and half in the low water at the margin. The shrimp net or 

 shove net must theu be used as a shovel and the eels are shaken out of the 

 weeds into it. It is surprising the (juantities of the eels that can thus be found 

 in a »shovelful« of Zostera. The same method eau be used where there is a 

 rich algal vegetation in low water (where one can wade), for exaraple, in the 

 western pait of Holbæk Fjord, where great clumps of Chætomorpha linum (Hør) 

 conceal quautities of small eels and also larger, up to ca. 30 cm. in size, in their 

 entangled masses. On quiet warm, sunny days in June — July a quantity of small 

 and a number of larger eels can be taken iia this manner. Ouo need ouly be 

 dexterous in fishing, the more so the larger the eels are. When they are so large 

 as 20 cm., it becomes difficult to catch them in quantities by this method; they 

 are then too rapid in Iheir movements. It is thus difficult to determine the pre- 

 sence of a year's group, the maximum of which falls at 23 — 24 cm., and this also 

 has the result that the tables seldom show a distinct group-limit at 17 cm. 



That these small 1 — IV2 year old eels are really only found in fresh water 

 or like a fringe aloug the coasts at suitable piaces — which would be a parallel to 

 the occurrence of the O-group of the plaice in the bottom-stages — I will not 

 maintain. It is quite probable, that just these masses of sea-weed offer very 

 favourable conditions with regard to temperature and food ■ — but the conclusion, 

 that these small eels could not live in the summer time, for example, in the 

 Zostera-belt where indeed the large eels occur in such large numbers, would be 

 too hasty. To find them in large numbers in deep water is however a difficult 

 matter; we find single specimens now and then entangled in the blades of Zostera 

 taken in the seines. 



Later in the summer or autumn the eels — not only the small — leave the 

 tang-margin or algal vegetation along the coasts and move out into deeper water. 

 The period is somewhat different round about the Danish fjords. At Seden Strand 

 (Odense Fjord), where a quantily of small eels was living in May in a dense and 

 low algal vegetation near the margin, they had already moved out in July; in the 

 beginning of October at any rate they had disappeared. — the eels there belong 

 to the II, and III groups; O and I groups were extremely sparsely represented (see 

 Tab. 2, column c). — In Holbæk Fjord, where many eels of the I, II and III 

 groups had lived in June in the algal vegetation in low water, none were to be 

 found anywhere at the end of September; the algal vegetation certaiuly had broken 

 loose there; along with the washed up Zostera it formed a huge fringe along 

 the beach, but this housed no eels. At Struer on the other hånd they were very 

 numerous under the washed-up Zostera even on the 20th of September. 



The distribution of the I group is however not so regular that it can be 



