FOOD FOR YOUNG SALMONOID FISHES. 843 



Lot 10, Atlantic salmon numbering (June 7) 1,196, kept in one trough and treated 

 as follows : 



June. — Fed until 9th somewhat irregularly on wild live food collected from pools and 

 other open waters; from 9th to 30th on chopped meat 2 to 4 times daily; mud baths on 

 5 occasions; cleaned daily. 



July. — Fed chopped food 4 times daily the entire month; mud baths daily till 

 29th; cleaned daily. 



August. — Fed chopped food 4 times daily; cleaned daily. 



September. — Treated as in August, but on 29th transferred to a 5-foot white varnished 

 trough outdoors. 



October. — Treated as in September until the 17th, when they were counted. 



The losses by death in lot 10 from June 18 to October 17 were 611, leaving 

 585" survivors, which were found October 20 to average in weight 30.66 grains (199 

 centigrams). 



Lot II, Atlantic salmon, numbering (June 7) 1,195, was treated almost exactly the 

 same as lot 10, the points of variation being quite unimportant. Counted October 17 

 and weighed October 23. There were 538 survivors, and their average weight was 



26.83 grains (173 centigrams). 



Lot 13. Atlantic salmon, numbering (June 7) 1,864; treatment as follows: 



June. — Kept in 2 troughs; fed on entomostracans and insects till June 9, after that 

 chopped meat, 6 times daily; mud bath 3 times. 



Jidy. — Fed on liver until 3d, on which day feeding of larvae was begun; mud bath 

 daily until 29th ; cleaned daily. 



August. — Fed fly larvae 6 times daily (with some irregularity); cleaned every other 

 day. 



September. — Treated as in August. 



October. — Treated as in August until 23d, when counted and weighed. The 1,447 

 survivors weighed on the average 43.84 grains (284 centigrams). 



It will thus be seen that the fish fed on butcher's offal attained a mean 

 weight of 30.66 grains (199 centigrams) in one lot, and 26.83 grains (173 centi- 

 grams) in the other lot ; while the fish fed on fly larvse attained a mean weight of 



43.84 grains (284 centigrams), a difference of 53 per cent in favor of the larvae 

 regimen. 



A similar comparison between several lots of landlocked salmon reared the 

 same summer shows a slight difference in favor, also, of the larvse regimen. 



The record for 1891 affords data for the following tabular statement, which 

 exhibits the results obtained from the feeding of 39 lots of Atlantic salmon in 

 wooden troughs of the standard size, all treated alike except in the matter of 

 food. Butcher's offal was given to 14 lots of them through the entire season 

 and the other 25 lots received fly larvae exclusively from June 22 to the date of 

 counting and weighing, which was from October 15 to October 29. 



a This heavy loss in numbers was the result of an epidemic that attacked the fry in June, irrespective 

 of the food or special mode of treatment. Of the total mortality in lot 10, there were 561 deaths in 

 June, 45 in July, 3 in August, 2 in September, and none in October. 



