oj the Fishery Board for Scotland. 



371 



It will be observed both from the averages and the curves that the 

 growth of the two sexes is at first fairly equal, but that after from about 

 160-170 mm. (6|-6f inches) the growth of the males becomes greatly 

 retarded, while the females continue growing almost as rapidly as before. 

 These differences are associated with the attainment of sexual maturity 

 at an earlier stage in the male than in the female, as occurs in the plaice 

 and long rough dab. The male appears to reach maturity a year earlier 

 than the female, namely when two years old, while the females do not 

 spawn until their third year. 



The dabs of the Sol way, like the plaice, grow more slowly than the 

 dabs on the East Coast. The particulars of a number of collections at 

 various dates will be found in the Table on page 420, and curves 

 representing the first and second series in some cases are given on Plate 

 XV. The measurements indicate that the fii-st series, or brood of the 

 year, reaches a length of only about 50 mm., or two inches, in the 

 autumn. In these cases also it is necessary to introduce a correction for 

 the smaller dabs which have escaped capture, the minimum size of those 

 taken being usually from 33 to 37 mm., and the maximum size of those 

 belonging to the group about 60 or 63 mm. 



If the same method is adopted as was applied to the series from 

 Aberdeen Bay, the range and average size of the group at the various 

 dates in the Sohvay becomes modified as follows : — 



These averages and ranges must be regarded as approximate, but 

 they fairly indicate the growth of this fish in the Sohvay, which is also 

 indicated by the curves. 



The second series is usually imperfectly represented, but in some cases 

 the curve is fairly symmetrical. On 26th October 179 specimens 

 ranged from 65 to 112 mm. (2^^^ to 4-jL. inches), with a mean size of 

 81-6 mm., or 3| inches. In this case the older fishes were not present 

 in proper proportion, but taking the limits of the series as described, the 

 amended mean size would be about 88-5 mm., or 34 inches. This would 

 represent the mean length of a dab in the Sohvay when al)Out seventeen 

 months old, and show the apparent increase in a year from the first 

 series of 4-4-5 mm,, or 1| inches. On 27th November 156 specimens 

 ranged from 66 to 107 mm., the mean size being 83-8 mm., or 3f^ inches. 

 On 10th October, 145, with a range from 66 to 97 mm., had an average 



