170 DEPARTMENT OF THE NATAL SERVICE 



8 GEORGE V, A. 1918 



to October 6. They all showed, if any, only slight marks, and no evident fungus. 

 From that date on, from 15 to 30 per cent (2 to 4 out of every dozen) of the fish 

 taken each day from three traps near the hatchery, of which records were kept, 

 showed signs of the disease, and were rejected. The fish from a trap 2^ miles 

 up the river showed twenty-six affected out of a total of fifty-two on October 6, 

 twenty-two out of 40 on October 8, and three out of thirteen on October 11, 

 apparently showing a steady improvement as if the infected fish had passed up 

 the river. Up to nearly the 8th of October the salmon in the pond did not seem 

 to be as active (jump as much) as in previous years, but since that date there 

 has been a marked improvement. 



"Last year (1914) there were 2,636 salmon in the pond. This year the 

 pond has been enlarged and is from one-quarter to one-third larger than last 

 year. The number of fish that had been placed in the pond previous to Sep- 

 tember 30 was 2,308. 



" This disease has not been noticed in the salmon in any year previous 

 to this, although salmon in the Gaspe region are reported to have had fungus 

 disease last year." 



From a comparison of the numbers of the fish and the sizes of the pond it is 

 evident that there has been far less croAvding of the fish this year than last. As to 

 temperature, the Monthly Weather Reviews of the Meteorological Service show that 

 at Chatham, 20 miles from the hatchery at the mouth of the Miramichi river, the 

 mean monthly temperatures for the months of August and September, 1915, are only 

 slightly (-6° and -2°) above the averages for those months for the past forty years. 

 And for the month of September both the mean temperature and the maximum tem- 

 perature are lower than for the same month in 1914. 



The temperature records for the water at the hatchery are incomplete. Tem- 

 peratures were observed in the hatchery from August 30 to September 20. The records 

 show a range from 50° to 68°F., with an average temperature of about 58°. Tem- 

 peratures have been observed in the retaining pond from October 6 to 20, and show 

 a range from 46° to 52°, the temperature remaining comparatively uniform during 

 that period. Temperatures observed in the hatchery from October 14 to 2'0 show that 

 on bright days the temperature in the pond is two to three degrees higher than in the 

 hatchery, and on cloudy days about the same as in the hatchery. Judging from this, 

 the temperature in the pond has at no time since fish were put in (September 11) 

 been higher than 65°F. Temperature does not appear to have been a special causative 

 factor in 1915. The gradual lowering of the temperature has doubtless helped to stop 

 the spread of the disease, Mr. Sheasgreen stating that on October 20 no new diseased 

 fish were appearing. 



As to the place of origin of the disease, the presence of diseased fish among those 

 caught in the traps over a considerable period of time indicates that the disease was 

 present for some distance up and down the Northwest Miramichi river. Diseased 

 fish were not noticed among those taken from the traps until one week after the 

 disease had been observed in the pond. Mr. Sheasgreen states that he and his 

 assistants buried all the fish removed from the pond. This obviates the possibility 

 of fish from the pond having carried the infection to the fish in the river, although 

 not the possibility of the pond having served as a source for the distribution of the 

 infection up and down the river. 



The avenue of infection appears to have been chiefly through abrasions of the 

 skin. The principal parts seen to be affected in the early stages of the disease were: 

 the tip of the snout, the margins of the jaws, the top of the head, and the middle line 

 of the back, and the margins of the fins. These are the parts most liable to injury in 

 the traps or in the cars used for transporting the salmon to the retaining pond. An 

 examination of the fish caught in the traps and brought to the retaining pond on 



