226 



Part HI. — Twenty-fourth Annual Report 



HADDOCK (Gadus ceglefinusj. 



The number of haddocks measured was 6682, making, with those whose 

 measurements are dealt with in the two previous papers referred to, a 

 total of 28,760 specimens of this species. The collections were partly 

 from Aberdeen Bay and neighbourhood and partly from the Moray Firth ; 

 the measurements in one-centimetre grouping are given in the appended 

 Table XXII. 



A collection made on 15th January 1902 at the "Doghole," off 

 Aberdeen, in 57 fathoms, 802 haddocks, most of them belonging to the 

 first group, or fish of the previous spawning. These numbered 775, 

 measuring from 150mm. to 210mm. (5g-8| inches) ; most were aggregated 

 between 16cm. and 19cm., the apex of the curve formed by the measure- 

 ments being at 17 5, which was also the mean, while the arithmetic 

 average was 180-5. The second group was represented by only a few 

 fish, from 240mm. to 324mm., or near it, and the computed average size 

 was 286*8mm., or about lTfg- inches, the annual increment being thus 

 about 4 r 3 ^ inches. 



On 13th May, in the same year, another lot of 596 haddocks was taken 

 on the same ground, in 52 fathoms, most of them belonging to the first 

 group, now over one year of age. They measured from 145mm. to 

 239mm. (5|-9| inches); most were between 17cm. and 22cm., the apex 

 of the curve was at 19'5cm., and the mean was the same (nearly 7| 

 inches). The growth in the interval of about 118 days was thus approxi- 

 mately 2cm., or | of an inch. The second group was represented by only 

 a few fishes, from about 25cm. to 32cm., or more. 



On 31st October 1903 a large collection of 1249 haddocks was obtained 

 in Aberdeen Bay, in 8-12 fathoms, and the measurements are of some 

 interest, as three groups at least are well represented, and a considerable 

 number of them —all those above 27cm., and many below that size — were 

 differentiated according to sex (fig. 7a, pi. XII.). It maybe said at once 

 that, contrary to the rule among flatfishes, the males and females are of 

 approximately the same size, and thus grow at the same rate, though the 

 females are in excess as to numbers. The first group, that is to say, 

 haddocks approximately seven months old, ranged in length from 136mm. 

 to 207mm. (5|-8J inches), most being between 14cm. and 19cm.; the 

 mode was at 16cm., and the mean at 16*5cm., or 6| inches. 



The second group extended from 217mm. to 310mm. (8^—12^ inches); 

 most measured from 25cm. to 30cm., the apex of the curve was at 27cm., 

 and the mean was 27 '5cm., or a little above lOf inches. The division 

 between this group and the third group is very distinct in curves made 

 on *5cm. grouping, at 31cm., and it is the same for the males as for the 

 females. These fish were about one year and seven months old. 



The third group extended from 31cm. to about 38cm., the bulk of the 

 haddocks were between 32cm. and 35cm., the mode is at 33cm., and the 

 mean is 33 '5cm., or 13^ inches. This group is partly fused with the last, 

 and it is to be noticed that in the '5cm. curves there is a slight depression 

 at 34cm., both with regard to the males and the females, suggestive of 

 two groups. 



The means of the three groups, taking the last provisionally as one, are 

 thus a? follows : — 



[Table. 



