of the Fishery Board for Scotland. 



197 





ll U. Ill 1 JCI UL 



Fish. 



xxtiiigc in 



Length. 



Size. 



28th December 1903 . 



73 



46-65mm. 



oG'Smm. 



23rd January 1904 . . 



57 



47-68mm. 



57 "4mm. 



1st April 1904 .... 



84 



47-70mm. 



56 *2mm. 



As already stated, the locality of the collections in December and April 

 were the same, and the facts show how much retarded the growth of 

 this fish may be during winter. 



In previous collections, described in my paper in the Twentieth Annual 

 Report, numbers of these small long rough dabs were secured, and the 

 average length in some cases may be referred to. The facts show that 

 the growth of this somewhat deep-water fish does not materially differ in 

 the north-eastern parts of the North Sea as compared with the Moray 

 Firth. In the deep water off the Shetlands, on 31st August and 4th 

 September, the average size was 48 - 3mm. and 48'4mm. On 16th— 19th 

 October it was 53'3mm.; on 11th December it was 54'4mm., and on 19th 

 May 68 , 4mm. Off Aberdeen Bay, on 21st August, 11 specimens had an 

 average length of 53mm.; on 16th December the average length of 116 

 specimens was 65'5mm. On 4th July, in from 83-85 fathoms, off 

 Kinnaird Head, 146 had an average length of 98'3mm. (3J inches). It 

 is thus clear that the growth of this fish, as formerly remarked, is slow, 

 and that when one year old its average length does not greatly exceed two 

 inches. 



In some of the collections the older groups are well indicated. In that 

 of 28th December, off Burghead, the sexes were not completely separated, 

 but in the lot of 23rd January they were. The females in the second 

 series in this collection range in length from 92mm. to about 129mm. 

 (3§-5^ inches), the average being about 112mm., or 11cm. (4| inches). 

 The males vary in size from 89mm. to 118mm. or thereabout, and the 

 average size is a little over 10cm. (or 4 inches). The increase in length 

 from the previous annual series is thus about 5*5cm., or 2| inches ; in 

 other words, the females at this stage grow about that more in the course 

 of a year. The difference in the case of the males is less, viz., from 

 57mm. to about 103mm., or 4'5cm., a little over If inches. 



The curve in this case shows a somewhat more rapid growth of the 

 females than the males, the latter lagging behind, and the fact suggests 

 that the males are approaching reproductive activity. I have shown 

 before that males may be sexually mature when scarcely 5 inches 

 (127mm.) long, and may show testes half developed when only 3| inches 

 (89mm.) long. The date of this collection about coincides with the 

 beginning of the spawning season, and is more than three months distant 

 from its close, and thus probably some of the males would reach repro- 

 ductive length during the spawning season. It is much more likely that 

 the third series represented in the collection is the chief reproductive 

 series. In it the males extend in length from 11 '5cm. (4| inches) to 

 16cm. or over (6| inches), the average size being about 13*5cm. (5| 

 inches). This group is very nearly three years of age. 



The females in the third series are widely separated from the second, 

 so that, in the curve, the curve of measurements of the males of the third 

 series is intercalcated in the gap between the curve for the second and 

 third series of females — a usual circumstance among flatfishes at the 



