396 Part III.— Twentieth Annual Be.port 



From 31st July to 18th October, when the mean size was 223-2 mm., 

 or 8^1 inches, the increase amounted to other 30'7 mm., or \\ inches, the 

 total mean increment in the 141 days being 7 1*9 mm. (2^| inches). In the 

 same period of 141 days the smallest grew from 113 mm. to 179 mm., an 

 increase of 66 mm., while the largest increased from 189 to 267 mm,, 

 an increment of 78 mm. {^j^ inches). In some of the hauls in 

 autumn the average size, as computed from the measurements, exhibited 

 not an increase, but a decrease. An examination of the curves, and 

 in some cases of the range alone, makes it clear, however, that this 

 diminution is owing to the imperfect representation of the larger fishes. 

 The numbers of the whitings of this series caught in autumn diminishes 

 owing to offshore migration, and the earliest to go are the larger ones. 

 On 15th January only five were taken, and their average size was 

 227*2 mm., or close upon nine inches. On 30th May the same group — 

 then beginning their third year — measured from 219 to 311 mm., the 

 computed mean size being 251 "9 mm., or 9i|^ inches. Since the mean size 

 of the previous series on 30th May was 151 "3 mm., the increment in a 

 year amounted to almost exactly 100 mm,, or about four inches. 

 It will also be seen from the Table that from 8th-13th October 1900 to 

 18th Octeber 1901 the increase in the mean length was from 121*0 mm. 

 to 223*2 mm., a similar increment in the year of about 100 mm., or 4 

 inches, and this amount agrees with the mean annual increment deduced 

 from comparison of the averages. 



This series of whitings in their second year was represented in hauls 

 elsewhere. In the Cromarty Firth on 1st June 78 whitings belonged to 

 the series, ranging from 119 to 198 mm., the average size being 161*4 mm., 

 or 6g inches, and the curve formed is symmetrical. In the deep water 

 off Aberdeen on 28th June, in 65 fathoms, 114, ranging from 141 to 

 212 mm., had a mean size of 181*1 mm. (7g inches). The curve, however, 

 is imperfect, the fishes not being present in due proportion, and a 

 more accurate mean size would be about 186 mm. At the same place on 

 30Lh July very few whitings were taken, and only seven apparently 

 belonging to this series. On 21st August seventy were taken, measuring 

 from 174 to 252 mm., and with an average length of 214*9 mm., or 

 84 inches. On 3rd September eight caught had a range from 150 to 

 2 12 mm., and a mean size of 182*6 mm. — obviously unrepresentative. On 

 5th November nine, ranging from 223 to 283 mm., had an average size 

 of 255*7 mm. On 28th November nineteen ranged from 198 to 

 287 mm., the mean size being 242*3 mm. On 16th December they 

 were more abundant, and the curves are satisfactory, the 207 fishes 

 ranging from 192 to 278 mm. and having a mean size of 231*8 mm., or 

 9g inches. On 15th January 1902, 126 of this series ranged from 

 194 to 277 mm., the average size being 231*1 mm. 



It will be observed that this series was scantily present in the deep 

 water off Aberdeen in the summer and more abundant in the bay, while 

 the opposite occurred in December and January. More correct averages 

 and ranges would probably be obtained by combining the series from the 

 two localities. Owing to the very small numbers taken in the deep water 

 in summer the combination would only slightly affect the averages for the 

 bay, but in November, December, and January the combination gives the 

 following ranges and means : — 



28-29 November, 95 from 192 to 287 : average 224*8 mm. 

 16-17 December, 249 „ 189 „ 278 : „ 226*7 „ 

 15 January, 131 „ 194 „ 277 : „ 230*9 „ 



In the collections from the Firth of Forth this series (II.) was well 



