of the Fisher ij Board for Scotlavd. 



555 



The growth of the plaice in Aberdeen Bay, according to their averages, 

 appears to be somewhat more rapid than in the Dornoch Firth, but it is 

 much the same as at the more open parts of the coast off Lossiemouth. 

 The curves, however, for these hauls show that with the exception of 

 the first and second groups (III. and IV.) in the Lossiemouth haul the 

 series are not proportionally well represented. 



It would be of interest to determine the rate of growth of the various 

 older series in the intervals between the hauls, as I have done with the 

 first series, but this is made very difficult in many cases owing to the 

 impei'fection of the groups. In other cases it is only possible to make 

 comparison between groups which were pretty equally represented in 

 the hauls at diflferent periods, and this has been done for Aberdeen Bay. 

 Particulars regarding the fourth series are as follows : — 



It thus appears that during the summer, in the five months from the 

 beginning of June to the beginning of November, plaice of this size- 

 about lOg inches — increase in length by between 50 and 60 mm., or 

 two to two and a half inches, which would leave over 30 mm. to be added 

 during the seven months of the year remaining. It appears that 

 growth is not arrested to the same extent in these older fishes during 

 the winter as with the first series, a result which might be expected 

 from the fact that they live in deeper water at a higher temperature. 

 I have not sufficient data to elucidate the subject in detail, but the incre- 

 ment of Series II. from the beginning of November to the 30th of May 

 in the following year (when it becomes Series TIL) amounts to about 

 43-3 mm. ; while the increment of the next series amounts to 32 mm. 

 Most of this growth no doubt took place after Mai-ch. 



With regard to the second series, or plaice over a year old, my 

 observations, as stated, are not sufficient to show the inci-ements of 

 growth at different periods, but it is probable that their growth is not 

 arrested in winter to the same extent as happens with the first series, 

 since they are in deeper water — ejj., on 6th November in six or seven 

 fathoms. But from a combination of the results from the Dunbar 

 collections and the haul of 6th November it appears fairly certain the 

 increase in length in the second year amounts to betAveen 70 :ind 80 mm., 

 and that the average size in April, when the plaice are two years old, 

 will be probably about 150 mm., or nearly six inches. 



