OF THE NORTH SEA 
17 
No. 2] 
live more pelagically, a point which, however, owing to the small 
material at hand, ought to be submitted to further investigation. 
The average length found from the material is very variable as might 
be expected considering the small number of individuals. The only 
interesting feature regarding the mean length, which might be of some 
interest in further studies, is the comparison between the size of the 
net-caught and the trawl-caught individuals of the group. 
By a comparison of the samples from the autumn we find for 
the II-group: 
Trawl 
Nets 
Locality 
Sample 
no. 
Number 
Length 
Aver. 
length 
Number 
Length 
Aver. 
length 
Near , 
i 
16—22, 24—27 
16 
19—21 
19.5 
Dogger Bank f 
23, 28. 
— 
— 
— 
11 
21 26 
23.1 
29—31, 34. 
8 
20—23 
21.4 
— 
— 
— 
Skager Rack \ 
32—33 . 
— 
— 
— 
10 
21—25 
22.5 
Near 
( 
19 
19.0 
35. 
1 
— 
— 
— 
Ling Bank J 
36. 
■—- 
— 
— 
2 
20—24 
22.0 
As both the trawl-caught and net-caught samples from about the 
same locality were taken within a very short interval of time, the above 
tabulated figures give the impression that the larger individuals of the 
group habitually live more pelagically, while the smaller ones keep 
to the bottom. It is of interest to note, that the latter as shown, 
mostly have a length of about the length-limit usually accepted be¬ 
tween the „small herrings 1 ' and the „fat herrings". The difference in 
length between the three groups of trawl-caught and net-caught herring, 
is certainly due to the different locality. 
Resume. 
As stated at the beginning of this report Dr. Hjort by these cruises 
in the „Michael Sars" only intended to make some preliminary inve¬ 
stigations about the habitat of the younger age-groups of the herrings 
in the North Sea so as to get some starting-points for further researches 
into the question. 
