84 

 THE SPAWNING OF THE WHITING. 



By B. STOREOW. 



In previous reports short accounts have appeared of the spawn- 

 mg of the cod and plaice, and figures have been given showing the 

 stages in development for each day from spawning to hatching. 



In August of last year some 19 whiting were caught on a hne in 

 the vicinity of CuUercoats Bay. Three of them died from injuries 

 but the others are still Uving, and during April and May of this year 

 yielded a considerable number of eggs, so man}' that it was necessary 

 from time to time to place quantities in the sea in order that the 

 eggs would not die from overcrowding. Ever}^ year similarly the 

 eggs and larvae which occur in the plaice tank are placed in the sea 

 in the vicinity of CuUercoats. 



The first eggs appeared on the 14th of March, but were not 

 fertilised. On the 14th of April first and third day eggs were found 

 in the tank, and from then to the 23rd of Ma}^ first day eggs were 

 present every da3^ Eggs of this stage occurred in numbers to the 

 8th of May, from then to the 14th only small numbers were spawned 

 daily ; from the 14th to the 19th they were again plentiful, and 

 afterwards to the 23rd very few newty spawned eggs were observed. 



As a rule spawning took place in the morning, but occasionally 

 later in the day, at odd times about noon, and once as late as 3 p.m. 



The diameter of the eggs varied from r09 to 1'15 mm. 



Samples of eggs were isolated in order to determine the period 

 between spawning and hatching, and as in the case of the plaice 

 this was found to vary. Eggs spawned on the 19th of April hatched 

 on the 28th, the tenth day from spawning ; the mean temperature 

 of the water for this period was 9-1° C. Others spawned on the 

 23rd and 30th of April and on the 7th of May, hatched on the 1st, 

 8th and 15th of May respectively, the nmth day from spawning ; 

 the mean temperatures of the water for these periods were 9*5° C, 

 9-8° C. and 9-2° C. 



The whiting were measured in the beginning of July, and the 

 sizes were as follows ; — 32 cm.-2, 30 cm.-4, 29 cm.-4, 28 cm.-l, 

 27 cm.-l, 26 cm.-l, 24 cm.-3. 



The periodicity observed in the spawning of cod and plaice, 

 and commented upon in previous reports, was also found in the 

 case of the whiting, but owing to the number of fish in the tank it 

 was to a large extent disguised. 



