85 



stage III., 60 were at stage III., 59 at stage IV., and 22 at stages 

 V. and VI. It is evident that a large number of these would 

 become spring spawners, and it is difficult to imagine that even 

 those at stage III. in the beginning of February would postpone 

 their spawning until the following autumn. 



Summer shoals have been shown to consist largely of maturing 

 herrings with three winter rings, and it is possible that the spawning 

 of large numbers of herrings with three winter rings in spring 

 may have an effect on the summer shoals of the same year. It 

 is desirable that our knowledge of the factors which influence 

 maturity be extended with the object of ascertaining the causes 

 of spring and autumn spawning, and also the causes of variation 

 in age when maturity is reached. 



The samples of winter herrings from Lerwick were taken from 

 the east of the islands, and not as in 1920 from the grounds between 

 Flugga and the Ramna Stacks. These grounds were little fished 

 during the past winter fishery, and on the few occasions when 

 catches were there made the sailing of the steamer to the main- 

 land made it impossible for Mr. Brown to forward samples. 



The sample of 12th February consisted of spawning fish 

 from grounds to the east of Bressay, and that of 20th May of 

 recovering spents from much the same locality. The latter sample 

 had suffered somewhat in transit, and it was difficult to tell with 

 exactitude the true condition of the gonads. It is certain the fish 

 were recovering spents, but it is doubtful if they were sufficiently 

 recovered to allow of them being placed at stage II. as in Table 

 II. Both these samples show a shortage of fish with six winter 

 rings, and over 30 per cent with seven and eight winter rings. 

 The February sample had 31 per cent, of fish with five winter rings, 

 and points to the fish which had three winter rings in 1919 being 

 fairly plentiful in some of the Shetland shoals. 



One sample only was received from the shoals off the north 

 coast of Sutherlandshire, 26th February, 1921, and this was con- 

 sidered by Mr. John Sutherland to be a fair sample of the herrings 

 landed at Peterhead from these grounds during the winter fishery. 

 The condition of the gonads points to the fish being spring spawners. 

 Fish with seven and eight winter rings comprised over 40 per cent, 

 of the catch. The same shortage of fish with six winter rings as 

 has been observed in other samples was present } but there was also 



