384 U. S. BUREAU OF FISHEEIES 



taking was discontinued when a sufficient number of eggs had been 

 obtained to seed the somewhat limited spawning areas within reach 

 of the station, and the remaining fish were allowed to ascend above 

 the racks to spawn naturally. 



Owing to some difficulty with the water supply while the eggs were 

 in the tender stage of development, the losses were somewhat above 

 normal, the total death rate during the incubation period amounting 

 to slightly more than 15 per cent. Early in October the water in 

 the hatchery became heavily charged with gas, its presence being 

 made evident through the formation of masses of tiny bubbles on 

 the baskets and upon the eggs. The constant bursting of the bub- 

 bles agitated the eggs, and whenever the slightest jar occurred they 

 were released in sufficient numbers to lift the entire egg mass from 

 the bottom of the baskets. During the night this movement among 

 the eggs caused many of them to accumulate at the lower ends of 

 the baskets, where they were in danger of smotherino;. The heavy 

 loss occurring during this period appeared to result entirely from the 

 unnatural movement of the eggs while in the tender state, as no in- 

 jurious effects of the gas other than its mechanical action were dis- 

 cernible. The cause of this abnormal condition of the water supply 

 was not definitely determined, but as it disappeared immediately 

 after fall rains and cooler weather set in, it is supposed to have been 

 a result of the warm dry summer. No prior occurrence of a similar 

 character has ever been experienced at the station. 



The artificial feeding of sockeye salmon in the slough pond in Lake 

 McDonald resulted less successfully than last year. This was attrib- 

 uted to the warm dry summer. By the middle of July, when the 

 water temperature in the slough had risen to 69° F., the fish showed 

 evidence of loss of appetite and became restless. In view of the con- 

 ditions the gates of the inclosure were removed shortly afterwards 

 and the fish permitted to leave at will. 



The result of a feeding experiment conducted by the Territorial 

 Fish Commission of Alaska during the year is mentioned as being of 

 interest in connection with salmon culture. Across the narrow neck 

 of a small arm of the sea on Gravina Island, a short distance from 

 Ketchikan, Alaska, a dam was constructed of sufficient height to 

 retain a mean depth of about 4 feet of water at low tide. Extending 

 above high water on the dam, a wire mesh inclosure of approximately 

 2,000 square feet was constructed, with the intention of retaining 

 therein only such fish as it was desired to introduce. The only change 

 of water in the pond thus formed was brought about by tide action, 

 the inclosure being flooded for an hour or more during high-tide 

 periods, and the entrance of fresh water was limited to the compara- 

 tively small amoimt of surface drainage after rains. Late in Febru- 

 ary some 50,000 humpback-salmon fry were placed in the pond. 

 The superintendent of the Yes Bay station, who visited this point 

 on two occasions during the spring of 1924, has made the following 

 statement: 



On mv arrival at this salt-water pond late in March the fish were just beginning 

 to take food. When I again saw them, on May 17, I was surprised to note their 

 rapid development. There was much variation in size, ranging from 1^ to 4 

 inches in length, but all of the fish appeared to be in most excellent condition. 

 The artificial foods given were beef liver and immature salmon eggs, both in the 

 fresh state. The total loss on the lot up to the time of my second visit was 

 reported to be about 15 per cent. 



