of the Fishery Board for Scotland. 



7 



The number of dead eggs which were removed from the hatching 

 apparatus was estimated at 3,056,000, or about 20 per cent, of the 

 total number collected, which is lower than usual. During the sea- 

 son the specific gravity of the water remained fairly constant at from 

 27*2 to 27'4. The mean monthly temperature in the pond was 37*9° 

 F. in January, 40*0° F. in February, 397° F. in March, 42*0° F. in 

 April, and 44*2° F. in May; in the hatching apparatus the mean 

 monthly temperatures were 40*0° F. in January, 42 0° F. in February, 

 40-6° F. in March, 42'8° F. in April, and 47-0° F. in May. 



The first larvae to be hatched out appeared on 7th February, and 

 during the season the young fishes were liberated in the sea in eight 

 lots, between the 19th February and the 28th May. With the excep- 

 tion of the first and the last lots, the fry were liberated off the 

 northern part of the coast of Aberdeen, in the neighbourhood of 

 Fraserburgh and Sandhaven, the fishermen of the district having 

 petitioned that that should be done. It may be mentioned that 

 reports have been received that unusually large numbers of small 

 plaice have been taken on the coast of Aberdeen, which is generally 

 attributed by the fishermen to the liberation of fry from the hatchery. 

 While it is not an easy matter to ascertain whether this opinion is 

 well founded, or whether the increase in the abundance of young 

 plaice is due to a natural cause or causes, apart from the liberation 

 of fry altogether, the results of the prolonged experiments in Loch 

 Fyne tend to support the view taken by the fishermen, and to show 

 that the quantity of young plaice in the neighbourhood may be 

 materially increased by piscicultural operations. These experiments, 

 which were fully described in *the Report for 1907, were carried on 

 for thirteen years, in the first six of which large numbers of fry were 

 liberated in the waters of the loch, while in the last six years no fry 

 were added ; and it was shown by periodic and systematic observa- 

 tions on the beach, that the young plaice which live there were found 

 in rather more than twice the abundance in the years when fry were 

 liberated than in the years when no fry were set free. 



The number of the eggs of the plaice collected from the spawning 

 pond, and the number of fry hatched out and liberated in the sea, in 

 the various years since the hatchery was established at the Bay of 

 Nigg, are as follows : — 



Year. 



Eggs Collected. 



Fry Liberated. 



1900 . 



43,290,000 



31,305,000 



1901 . 



65,377,000 



51,800,000 



1902 . 



72,410,000 



55,700,000 



1903 . 



65,940,000 



53,600,000 



1904 . 



39,600,000 



34,780,000 



1905 . 



40,110,000 



24,500,000 



1906 . 



7,486,000 



4,406,000 



1907 . 



1,627,000 



1,282,000 



1908 . 



15,332,000 



12,296,000 





351,172,000 



269,669,000 



The cost of the fish-hatching work as carried on at the Bay of Nigg, 

 in conjunction with the laboratory, is very small, amounting to an 



