116 DEPARTMENT OF THE NAVAL SERVICE 



6 GEORGE V, A. 1916 



12.00. The former has moved into the lighted space, raises its muzzle above the 



surface, and then swims back into darkness. 

 12.18. The same fish returns into the light, raises its nose above the Avater, and 



remains motionless. 

 12.23, It returns to the shadow. 



12.35. A small individual has passed into the light. 

 12.38. It returns to darkness. 



12.45. Another has gone into the light. 

 12.48. It returns to the shadow. 



July 28. 



Experiment II. 



10.10 p.m. Lamp lighted ajid room darkened. 



10.15. Big eel has gone into the light. 



10.55. Returns to darkness when a more intense light was made. 



11.00. The same fish has moved into the light. 



11.15. Has returned to darkness. 



11.25. The same one has returned, but only head in the light. 



11.36. It passes fully into the light. 

 11.50. Returns into the shadow. 

 ]2.05. Extinguished light. 



12.10. Turned on the light suddenly. One was in upper part of tray, and the others 

 that had remained most of the evening in the lower part had moved far up. 



Several evenings were devoted to the observation of these fish, but their actions 

 and movements were quite similar to those recorded above, except that the longer they 

 were kept in confinement, the less they seemed to avoid the light. 



It was thought that more satisfaotoiy results could be obtained by conducting 

 the experiments under more natural conditions, and for this purpose the outlet of 

 lake Bocabec was chosen. It was admirably suited for the purpose, flowing through 

 a level little valley, had a smooth clay and sandy bottom, water from 5 to 7 inches 

 deep, with a gentle current, and banks regular, grassy, and slightly undermined, here 

 and there affording a cool retreat for the eels during the day. 



Two wire screens about 10 rods apart were stretched over the stream, there about 

 12 feet wide, and sunk some inches into the bottom and banks to prevent the eels 

 from escaping by borrowing. 



Two large bullseye lanterns were arranged, one on each side at the level of the 

 water directly opposite and facing each other. The arrangement made rendered it 

 impossible for a fish to pass without being seen by the observer. 



Seven large eels were got from a fisherman who had caught them in a herring 

 weir that day, and were placed in the pond just before noon hour, August 15. They 

 showed the effects of a sudden change from salt to fresh water in a more marked 

 manner than the first lot did on being transferred from a fresh to a brackish medium. 

 Restlessness, rapid breathing, gasping, swimming from one end of the enclosure to 

 the other, seeking to surmount the barrier, wheeling and moving rapidly to the other 

 end, opening the mouth widely and swelling the 'gill region to a marked degree; all 

 these symptoms continued with gradually lessening intensity until about 6 p.m., when 

 most of them were quieter and breathed more moderately and regularly. During that 

 afternoon and next day, they showed no tendency to huddle or seek conceahnent, but 

 lay out in the open stream, one here and one there, but on the third day they were 

 active in seeking hiding places and huddled. It would seem as if the open free life 

 is the natural one to these large fish, but it is probably otherwise with smaller ones, 

 though young ones from 5 to 7 cm. in length will swarm up an inlet from the sea all 

 day under direct sunlight. 



