13 



land's Hatchery, Bay of Nigg, near Aberdeen, woiild be 

 of immense value in all our hatching and rearing work. 

 Once the pond was stocked with fish, re-stocking would 

 be unnecessary except, perhaps, occasionally to compensate 

 for death due to unavoidable causes. The pond would 

 also encourage the growth of natural food for the larvae, 

 and thus place us, to some extent at least, beyond the 

 influences of weather and tides which so readily aifect 

 the floating food supply of the sea in a neighbourhood 

 such as that of Piel. 



During the season of 1902 we had 00 plaice and 150 

 flounders in the tanks. The latter were collected in 

 Barrow Channel, as in former years, by Mr. Wright. 

 The prolonged period of cold weather in February, and 

 the consequent low temperature of the air and sea, had 

 considerable effect in retarding the maturing of the fish. 

 The first fertilised eggs were collected on March 6th, and 

 the last on May 21st. During the spawning period over 

 thirteen millions of eggs were collected and incubated, 

 and these eggs produced nearly twelve millions of fry, 

 which were set free about the centre of Morecambe Bay, 

 a locality where we have found, in various surface tow- 

 nettings, the fry of cod and plaice naturally hatched in 

 the sea. In the case of the flounder the period of incuba- 

 tion varied from eleven days at the beginning of the 

 season to seven days at the end, because of the increase 

 of temperature. The plaice at the beginning of the 

 season took seventeen days to incubate, and fifteen 

 towards the end. The loss of eggs during incubation 

 from all causes was slightly over 11 per cent. 



The following tables show the number of eggs collected 

 and fry set free, and also the specific gravity* and tem- 



''■'■ The figures given are simply the uncorrected readings taken 

 with the Kiel areometers. 



