REPORT OF COMMISSIONER OF FISH AND FISHERIES. XLVII 



The Pacific salmon fry placed in the ponds for experimental purposes 

 weighed 1 pound 10 ounces to the thousand on July 1. These were 

 confined in a pond about 8,000 square feet in area. In January, 1898, 

 they weighed 41 to the pound, and in June the average weight had 

 increased to 12 to the pound. Great dissimilarity was noticed in the 

 color and shape of .lake-trout eggs taken from different waters. For 

 example, the eggs of the lake trout taken at Willoughby Lake closely 

 resemble those of the landlocked salmon, and aie much larger than 

 those from Caspian Lake, 600 of the Willoughby Lake eggs equaling 4 

 fluid ounces, while it required 800 from Caspian Lake to fill the same 

 measure. It was also noticed that the fry hatched from the Caspian 

 Lake eggs were much smaller and more active. 



During April, as the troughs in the hatchery were much crowded, 

 some of the fry were transferred from them to the nursery ponds, 10,000 

 to each pond. These ponds had not been used for six months, and were 

 supplied with water from Sleeper River. The fry in the ponds had the 

 same care as in the hatchery, except that it was impossible to clean 

 them as thoroughly. No unusual mortality was observed, and at a 

 careful examination of the outlets, to see if the fry were escaping, every- 

 thing appeared to be perfectly tight; but on June 6, when these fish 

 were taken from the ponds for shipment, only 25 per cent of the number 

 originally placed there were found. It is difficult to account for the 

 disappearance of the balance, though it was possibly due to cannibalism, 

 as the fish taken from the ponds were at least three times as large as 

 those of the same age taken from the troughs. This larger growth may 

 to some extent be due, however, to higher temperature of the water, and 

 to the presence of some natural food. It was observed that under the 

 same conditions — i. e., with the same number of brook trout, steelhead 

 trout, and landlocked salmon, in ponds of equal size — the landlocked 

 salmon stand a much higher temperature than any of the others. 



The food used at the station has consisted principally of livers, with 

 the addition of insect larvae obtained from the refuse of livers, crows, 

 woodchucks, etc. One woodchuck produced 1 quart of maggots. 



Enemies of the fish have been the source of but little trouble during 

 the past year, except in the case of the kingfisher, many of which have 

 been killed. Iu October a colony of muskrats made their headquarters 

 in one of the ponds, and before they had been discovered had made 12 

 holes in the banks, one of which caused a leak. These animals were 

 shot and trapped. All were males, indicating that the males precede 

 the females in the preparation of the winter homes. Mink were seen 

 occasionally along the river, but no trouble was experienced from them. 



Several landlocked salmon from the plants made by the Commission 

 were caught with hook and line at Lake Morey, Fairlee, Vt., in May, 

 1897, and it is expected that in a few years this lake will afford a valu- 

 able field for the collection of this species. In May, 1898, a landlocked 

 salmon weighing 4f pounds was taken at Caspian Lake. In Sleeper 

 River, which is the source of the water supply for the St. Johnsbury 

 Station, rainbow and brook trout, quinnat salmon, Atlantic salmon, 



