FISH-CULTURE. 207 



This table is almost perfectly accurate for Loch Leven trout 

 ova. For salmon ova, the figures are about '04285 too great. This 

 is in practice easily corrected by subtracting four-fifths of a 

 degree before using the table. Thus, for salmon ova, the value of 

 the percentage of incubation for twenty -four hours, with the water 

 at 46 F., would be 1*351, not 1*428, and so on. Similarly, if the 

 time of incubation of any variety or species be known, the table 

 will show, at any stage the period of which has been determined, 

 whether the embryo is in advance or retard of its normal, and this 

 no matter how varying the temperature. In this way experi- 

 ments all over the world can be compared, and results deduced 

 with great accuracy. 



SEASON 1875-76. FISH-CULTURE. 



The fish-cultural work this season consisted in spawning burn- 

 trout and Loch Leven trout ; no hybrids were made. 



On October 20th I examined the trout S. fario in Craigend 

 dam ; none of them seemed to be within a week of spawning. I 

 ran the dam dry, and bailed out the last drop of water, and got 

 out all the trout, including the big Loch Leven female " Queichy," 

 so called from her having been caught in the North Queich, near 

 Milnathort. This was the spawner brought last year from Kin- 

 ross, whose eggs were impregnated by the milt of a sea trout 

 (Exp. 8). The male Loch Leven trout had unfortunately fallen a 

 prey to an otter ; at least it was found on the bank of the dam 

 with a piece eaten out, and shortly afterwards the track of an otter 

 was seen in the burn leading from the dam. I placed the trout 

 first in the Francis Box ; but although there was a good flow of 

 water, I found they were too crowded ; and as the long pond (now 

 called the upper 100-feet) had not yet been used for fish, I turned 

 them into it, where they rapidly improved. The question of the 

 retention of spawning fish is of the utmost importance. At Howie- 

 toun it is solved by the construction of the ponds, and where the 

 stock-fish are bred from generation to generation this is the true 

 solution ; but in salmon-culture the fish must in many cases be 



