72 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



FISH HATCHING AT PIEL. 

 By Andrew Scott, A.L.S. 



The hatching operations carried on in the Spring of 

 1914 resulted in the liberation of just over thirteen 

 millions of fry, chiefly flounders as in former years. 

 Adult plaice for the spawning tanks were obtained from 

 Luce Bay in the late Autumn of 1913, by the kind 

 permission of the Fishery Board for Scotland, and were 

 kept in the tanks during the Winter. The flounders 

 were collected in Barrow Channel a few weeks previous to 

 the usual spawning time. 



The spawning of both plaice and flounders was 

 unusually late in beginning. The first fertilised eggs 

 were not obtained till March 23rd, two days later than in 

 any previous year, and nearly a month later than in 1913. 

 So far as our records show, there was apparently no 

 undue delay in fish spawning in the open sea under 

 natural conditions. Plaice eggs were found to be present 

 in the plankton collected in the central area of the Irish 

 Sea on February 17th, and in Port Erin Bay on the 

 26th of the same month. The lateness of the spawning of 

 the fish kept in our tanks compared with what takes 

 place in the open-air spawning pond at the Port Erin 

 Hatchery is probably largely due to the variation of the 

 temperature of the sea-water at the two places. At low 

 water in the neighbourhood of Piel large tracts of the 

 shore are laid bare, and in places that do not dry the 

 water becomes quite shallow. The exposed area soon 

 becomes cooled down, especially during continued frosts 

 or easterly winds, and when the flood tide sets in, any 

 increased temperature that it may possess is quickly lost 

 on coming into contact with the cooled area. In mild 

 weather the early flood water, on the other hand, may be 

 warmer than in the open sea. It is not always possible 



