+ 
January 13, 1923] 

NATURE 5! 
Breeding Places and Migrations of the Eel. 
By Dr. Jous. Scumipr, Copenhagen, 
"Gl an article in NATURE ten years ago (August 22, 
1912, p. 633) I gave a review of the position at 
that time of the question of the breeding grounds of the 
freshwater eel (Anguilla vulgaris), We had then been 
working for seven or eight years upon the question, and 
it was our intention to pursue the work further by means 
of investigations extending across the Atlantic. - 
In the ten years then following falls the period of the 
Great War. This rendered work at sea impossible. We 
research, partly from various trading ships plying on 
transatlantic routes, and partly from two schooners 
kindly placed at our disposal by the owners (1913- 
1914, the Margrethe, 90 tons; 1920-21, the Dana, 
550 tons). 
I shall in the following give a brief survey of the 
discoveries made regarding the breeding places of the 
eel since my article in NATURE in 1912, adding also 
some remarks on the immigration of the eel-fry to 

managed, however, partly before and partly after the 
war, to carry out an investigation covering the greater 
part of the northern temperate waters of the Atlantic, 
and the question, Where does the eel breed ? can now, 
in the main, be considered solved. At the same time, 
we have ascertained the duration and extent of the 
migrations of the eel-fry. 
The previous investigations had been undertaken 
with the well-equipped research vessel Thor, but its 
radius of action would not suffice for transatlantic 
cruises. From 1913 until 1921, when the Danish 
Government acquired the mine-sweeper Dana to replace 
the Thor, we were obliged to make our investigations 
from ships without any special equipment for marine 
NO. 2776, VOL. 111] 

Europe. For further details I must refer any readers 
interested to my recently published paper in the 
Philosophical Transactions. 
In my article in NATURE (August 22, 1912, p. 633) I 
‘summed up the position as follows: ‘ We cannot say 
as yet where exactly the spawning takes place, and but 
little more than that the spawning places must lie in the 
Atlantic beyond the Continental Slope, and that they 
must be in the Northern Atlantic.” 
The smallest (youngest) developmental stage of the 
eel then known to us was a larva of 34 mm. length. 
In order to say anything definite as to where in the 
1 Philosophical Transactions of the Royal Society of London, Series B- 
No. 385, vol. 211, pp. 179-208, 1922. 
