152 



Part Til. — Thirteenth Annual Report 



larger in a low temperature than in a high. 5. That development of 

 fish-eggs takes place also at temperatures below zero, when the specific 

 gravity of the water is sufficiently high to prevent it from freezing. 



As regards the hatched embryos or larval fishes, they seem to thrive satis- 

 factorily at all temperatures above zero. With respect to the temperatures 

 below zero, I am unable to say anything from experience ; but the fry at 

 the high temperatures, 12° and 14°C, were not so lively, which, I am 

 sure, was at least to some extent owing to the confinement in a small 

 portion of water. Fry of haddock, that had been hatched in water of 

 G° C, were exposed to a sudden change in temperature by being trans- 

 ferred to water of 0° — others were at once placed in water of 10° — and in 

 no case was I able to discover any particular effect from the change. 

 Immediately after their transference they appeared quiet and inactive 

 but they soon again showed their usual activity and vigour. 



