of th e Fishery Board /or Scotland. 



219 



bottom or ground fish. The lowest temperature of the bottom water 

 occurs about the middle of March, usually a little before the middle, and 

 in the latter part of the month the rise begins, which continues to increase 

 until about the middle of the following August ; thereafter it declines 

 until the next March. The maximum and minimum temperatures may 

 vary by a week or two in different years. W e see from the Tables that 

 the mean rise in April is 2*2 deg. F. above the temperature in March, 

 and in May there is an additional rise of 3*4 deg. F. 



Now it appears to be just at the time when the temperature of the 

 bottom water begins to rise that the gurnards first make their appearance 

 in the Firth of Forth area. They have been waiting, as it were, in the 

 open sea offshore until thi3 sign of the new season reaches them, and then 

 they begin to move inwards. And the temperature at which the inward 

 migration begins seems to be fairly definite. In Table I. it is shown that 

 only three gurnards were captured in February, and fifteen in March. 

 The particulars in regard to these are of interest, and are represented in 

 the accompanying Table : — 



Date. 



Station. 



Gurnards. 



Tempera- 

 ture of 

 Bottom 

 Water. 



Difference 

 from mean 

 Tempera- 

 ture. 







No. 



Size in inches. 







Feb. 18th, 1896. 



VIII. 



2 



12, 12. 



43 



+ 1-7° 



„ 19th, 1891. 



IX. 



1 



10 



42-3 



+ 0-7° 



March 13th, 1891. 



II. 



1 



4 



40-6 



+ 0-3° 



„ 19th, 1891. 



V. 



1 



12 



40-6 



+ 1-1° 



„ 21st, 1891. 



VI. 



1 



13 



40-6 



+ 0-6° 



„ 18th, 1890. 



IX. 



1 



13 



42-0 



+ 1-8° 



„ Hth, 1890. 



VI. 



1 





42-0 



+ 0-2° 



„ 14th, 1894. 



VIII. 





14 



40-6 



+ 0-6 n 



„ 29th, 1894. 



VII. 



I 



6, 10, 14, 14 



41-2 



+ 1-3* 



„ 30th, 1894. 



VI. 



9 



12, 14 



41-2 



+ 1-2° 



„ 30th, 1894. 



V. 



3 



10, 10, 12 



41-0 



+ 1-5° 



In all cases it will be seen that the temperature of the bottom water at 

 the stations where gurnards were captured in February and March was 

 above the mean for these months at these stations (vide Table IV.). In 

 St. Andrews Bay all the gurnards taken in March, fourteen in number, 

 were obtained in 1890. In that year two series of hauls were made at 

 the stations there : one series on the 3rd, 4th, and 5th, when the bottom 

 temperature varied at different stations from 40'5 deg. F. to 41*3 deg. F., 

 and exhibited a mean for the area of 40*9 deg. F. Both the mean temperature 

 and the station temperatures were higher than in March of any other year, 

 and one gurnard, 16 inches in length, was caught at Station II., where the 

 temperature was 40*80 deg. F. The second series of hauls was made on 

 March 26th, 27th, and 28th, when the mean temperature was 42-2 deg. 

 F., and the individual temperatures at the various stations ranged from 

 42*1 deg. F. to 42*3 deg. F. Thirteen gurnards were caught, as follows : — 

 I. II. III. IV. V. 



No. 5 4 10 3 



Size (inches), 16,16,14,14,11 15,15,13,13 7 ... 131,13^,13^ 

 Temperature. 42-1° 42-2° 42-1° 42"3° 42-1° 



When these facts are considered with those relating to the Firth of 

 Forth it appears that no gurnards are caught in these areas when the 

 temperature of the bottom water is below 40*5 deg. F. It is not until 



p 



