232 



Part III. — Twenty -fourth Annual Report 



As I pointed out in my previous papers, these very young whitings 

 have been leading a pelagic life, and now descend to the bottom when the 

 seasonal change of temperature makes the water there warmer than the 

 surface layers. 



Most of the fishes in this series were aggregated between 10cm. and 

 16cm., the apex being at 13cm., as well as the mean, and the arithmetic 

 average was 132mm., or nearly inches. The grouping of the larger 

 whitings is not very clear, but most of them measured from 21cm. to 

 30cm., the mean being about 25 , 5cm., or 10 inches, a difference of about 

 12 5cm., or about 4g inches from the average of the younger group. 



In a collection made on 29th December, 1903, 498 whitings were 

 obtained, nearly all belonging to the first group. Their sizes ranged from 

 115mm. to 180mm.; most were between 12cm. and 16cm., the greater 

 number, or the apex of the curve, being 14cm. (5| inches), which was also 

 the mean. 



The principal results in regard to the growth of the first group may be 

 tabulated as follows : — 





Date. 



Average Size. 



Smallest Size. 



Largest Size. 







Cm. 



Inches 



Cm. 



Inches 



Cm. 



Inche 



Dornoch Firth, 



22nd October, . 



11 



4f 



5-1 



2 



17-6 



71 



Do., . . . 

 Do., . . . 

 Do., . . . 



11th November, 

 27th December, 

 7th December, 



12 

 13 

 13-5 



i| 



H 



5-8 

 8-5 



3 



19-4 

 21-1 



7| 



Burghead, 

 Do., . . . 

 Do 



20th October, . 

 14th November 

 28th December, 



10-5 



12 



13 



H 



7- 5 



8- 1 

 7-5 



3 



H 



3 



14-6 



17- 4 



18- 5 



5| 

 7} 



Off Kinnaird, . 



23rd January, . 



12 



41 



7-6 



3 



16-5 



6* 



Smith Bank, . 



23rd October, . 



12-3 



4f 



8-7 



3* 



16-0 





Aberdeen Bay, 

 Do., . 

 Do., . . 

 Do., . . 



11th February, 

 29th March, . 

 31st October, . 

 29th December, 



13 

 14 

 13 

 14 



54 



5| 



si 



7-6 

 11-0 



5-6 

 11-5 



3 



4f 



21 



18-1 

 18-0 



7i 



The mean sizes of the second group of whitings varied as follows : — 

 Burghead — 20th October, 23'5cm., or 9| inches; 14th November, 27*50111., 

 or 10f inches. Smith Bank — 1st April, 24-5cm., or 9| inches. Aber- 

 deen Bay — 13th May, 22 5cm., or 8| inches ; 31st October, 22 , 5cm., or 

 10 inches. 



GREY OR COMMON GURNARD (Trigla gurnardus). 



The number of specimens of the grey gurnard measured in connection 

 with the observations in this paper was 5495, belonging to about 50 

 collections. 



Another paper in which the growth of this fish is dealt with was 

 published in the Seventeenth Annual Report.* 



The spawning period of the gurnard is prolonged, extending from April 

 to the latter part of August, and into September, or, according to Heincke 

 and Ehrenbaum, to October; spawning is at its height in the early part 

 of June. In May the duration of "incubation" is eight or ten days, but in 



*"On the Migratory Movements and Rate of Growth of the Grev or Common 

 Gurnard," Part III., p. 210. 



