of the Fisher 11 Doard for Scotland. 



851 



On 11th November 1901, a haul, also in Dornoch Firth in 8-10 

 fathoms, yielded 240 plaice which grouped themselves as follows : — A 

 first series comprised fifteen females and eighteen males ; the former 

 ranged from 165 to 203 mm., and liad an average of 182-9 mm., while 

 the males, from 138 to 195 mm., had a mean size of 176"8 mm., the 

 average for the group being 179*6 mm., or 7jj- inches. 



The second series was made up of sixty-two females, from 209 to 

 290 mm., with an average size of 254*1 mm., and eighty-one males 

 from 209 to 292 mm., and having an average of 246-4 mm. The 

 mean length of the group with the sexes combined was 249-8 mm., or 

 9i inches. 



The third series comprised twenty-two females from 294 to 369 mm., 

 with an average of 323-6 mm., and seventeen males from 297 to 

 364 mm., and with a mean size of 324-7 mm., the average for the 

 group being 324-1 mm., or 12J-jl inches. 



A fourth group contained four females with an average of 407 mm., 

 and twelve males with an average of 385-2 mm., the mean for the 

 group being 3909 mm., or 153 inches. Other eight females from 443 

 to 495 mm, appeared to form the fifth series with an average size of 

 469-6 mm., or 18| inches. Another female measured 662 mm. 



Another haul with the ordinary otter trawl in the same place on 

 the same day yielded a number of plaice of which ^365 females were 

 measured, the^ measurements grouping themselves into five series 

 corresponding very well to those first described, the respective 

 averages being 186-2, 249-1, 321-2, 390-4, and 460-2 mm. 



A haul off Lossiemouth on 3rd November 1900 yielded a number of 

 plaice among which four groups, comprising 450 fish, seemed fairly 

 well defined. The first had an average size of 188-3 mm., and a range 

 from 152 to 223 mm.; the second an average of 275-7 mm., and a 

 range of 228 to 310 mm. ; the third an average of 358-2 mm., and a 

 range of 313 to 401 mm. ; the fourth ranged from 402 to 464 mm., 

 with an avemge of 422-4 mm. There were also a number of large 

 plaice, all, or almost all, females, not easy to allocate. 



In considering the measurements above detailed it will be found that 

 the apparent mean annual increment of growth from one series to 

 another varies considerably, due, as indicated, to the true average not 

 being I'epresented owing to the imperfection of the groups. The differ- 

 ences between the average or mean size deduced for each successive 

 annual series, or the apparent increment of growth in a year from one 

 series to the other, are shown as follows for Aberdeen Bay, the series 

 being numbered according to their probable age. 



