236 EEPORT OF COMMISSIONER OF FISH AND FISHERIES. 



in a pojid where tliey had access to deep-water. Finally the bottom' of 

 the pond was covered with vegetation that had become established 

 there during several years when the dam was oat of use, and in its 

 decay it probably imparted some deleterious substances to the water. 

 But, from whatever cause, the mortality was such as to threaten the 

 speedy termination of the experiment by the total loss of the fish. 



It was decided to abandon the brook and construct a pound of brush 

 and netting in Allamoosook Pond, in which to keep the salmon that 

 should survive. This pound was built at the mouth of Craig's Pond 

 Brook, and inclosed an area of about twenty-five square rods, extending 

 from the shore to a point where the water was 7i teet deep. At this 

 depth nothing could be seen from the surface, the water being of a 

 brown color, like nearly all the pond and river water in Maine. The 

 pound was completed on the 27th, and the nineteen salmon remaining on 

 hand weie placed therein. Such was their condition, however, as the 

 result of their stay in the brook, that probably few, if any, lived through 

 the summer. 



Of the salmon received after this date, twenty-five in number, eighteen 

 survived until the close of the season in good health. The last salmon 

 were brought July 11, and after the 13th there was but one death. 



During the summer the level of the pond fell, till the depth of 

 water in the salmon pound was less than four feet. The average tem- 

 perature of the surface was 64°.7 F. at the close of June, 73° dur- 

 ing July and August, and as high as 62o.9 in September. The 

 bottom temperature was not observed, but as the depth of the water 

 constantly decreased until some time in September, when it was only 4 

 feet, it is probable that the temperature at the bottom was much higher 

 in August than in July. In view of this probabilitj', the fact of fewer 

 salmon dying in August (only one) leads to the conclusion that the 

 losses experienced in this pound were not the result of the heat, but of 

 the injuries received in capture and transportation. In short, all the 

 conditions attending their confinement appear to have been well suited 

 to their wants. The narrow space which the receding water left them 

 to swim in, being at the lowest ebb only 30 or 40 feet square, appeared 

 to cause them some uneasiness, but the walls of the pound were secure 

 and none escaped. 



Wiiile the pound was building nine of the least healthy salmon in the 

 brook were reipoved to Craig's Pond and turned loose. It is supposed 

 most of them lived through the summer, for a careful watch for dead 

 and floating salmon was kept up without discovering any. On several 

 occasions salmon were seen swimming near the shore of the pound or 

 leaping into the afr. It is probable that the fish retired to deep water 

 immediately on finding themselves at liberty,'and that the protection 

 there afforded against the glare of light, the character of the water, and 

 other circumstances were favorable to a recovery from the malady that 

 had attacked them and would have killed them if they had not been 



