ures oE the eel migration at a couvenient piace, I cliose the outlet at Kileu for a 

 seeond time. 



Concerning these last experiments tiie followiug report may be given. 



After waiting to no purpose in the moouless mghts of August for au 

 opportunity, when wind and stream would oiTer the necessary conditions for a 

 large outward migration of eels from Kileu at Struer, we at last got these condi- 

 tions on September 15th during the September moonless nights. 



The migration of the eels proceeded on such a large scale, that specially good 

 conditions M-ere present for the investigation of the influenceof light on the eels whilst 

 migrating. The current was ruuuiug out of the uarrows, which was a necessary 

 conditiou, and the night was dark, rainy with strong wind from the S.W. The 

 outlet of the cliaunel is ca. 40 feet broad and ca. 2 feet deep. It is closed by a 

 sluice or drawbridge with 3 openings over which is the pathway. The central 

 gate was now held open and a trap set opposite or outside it, so that but very 

 few at any rate of the migratiug eels could escape capture when they had passed 

 through the gate. The eels began to migrate about 8 o'clock in the evening and 

 by 9 o'clock ca. 100 Ibs. were taken, according to the estimate of two fishermen 

 who remowed the eels captured in the trap into a tub. 



The trap was now emptied, so far as this could be done under the cir- 

 cumstances, into the tub by the two fishermen who stood out in the outlet with 

 their boots on, and in the course of the next quarter of an hour, 9.10 — 9.25, ca. 

 50 Ibs. were taken according to tlie calculatiou of the fishermen. These were 

 likewise emptied into the tub and the light-projector was then set working from 

 9.25 — 9.40, in such a way that it only shone betweeu the arms of the trap and 

 the sluice-gate, the latter greatly cuttiug off the light from the inner parts of the 

 channel; only a quite narrow part of the water between the arms of the trap was 

 thus lighted. At 9.40 the trap was again searched and in it was ca. 1 Ib. of eels 

 (ca. 10 specimens), the majoritj' of which had stuck in the outer parts of the 

 trap or had remained betweeu its arms and the nearest corners of the sluice. 



To make no mistake about the matter, I again had the trap set in the 

 ordinary way without hght from 9.45 — 10, and in this time ca. 75 Ibs. were taken. 



I now went with the projector further up the channel, where the outlet 

 had its fuU breadth, ca 44 feet, in order if possible to get a sight of the migra- 

 tiug eels. 



This was easily done by quickly throwing the light over the water so that 

 the bottom was well lighted. On holding the light thus steady for a moment all the 

 eels disappeared from the illuminated part; they fled from this with great swift- 

 ness both up and down the stream. Turniug the light some few fathoms up the 

 channel, the eels were again seen. 



It appeared that so long as the projector was throwing its hght across 

 the outlet, very few eels came iuto the trap, where the two fishermen still watched 

 out in the water. I beHeve that only those eels came into the trap which were 

 between the latter and the streak of light. As soon as the light was removed from 

 the outlet, in a minute or two the eel-migration began again and was observed by 

 the fishermen at the trap. 



Whilst the light was shining steadily across the outlet, the bottom was 



