MACKEREL AND SUNSHINE. 



399 



year, does not therefore agree with the official figures for mackerel, with 

 the catches of the three sailing drifters, nor with the figure taken to 

 represent the Copepods. Any explanation of this discrepancy can only 

 be of a speculative kind, but it is probable that the steam drifters 

 fished much further west of the Scillies than the sailing drifters would 

 go, or than the International Stations are situated. If this is the 

 explanation of the difference shown, it would seem to suggest that in 

 May, 1906, there was some local factor at work on the grounds nearer 

 the shore which did not operate on those which were more distant. 



HUNDREDS 

 OF MACKEREL 



400 



500h 



200- 



100 



1902 



1903 



190^ 



1905 



1906 



1907 



Flu. 3. — Curve indicating the average number of " hundreds" (120 iish) of mackerel per 

 boat, lauded at Newlyn and Milford, in the month of May of the years 1902- 

 1907, by three sailing drifters belonging to Messrs. Peacock & Co., of Lowestoft. 



Before leaving the question of sunshine it should be stated that 

 curves representing the bright sunshine in the months of April and 

 May have not shown any kind of correlation with the quantities of 

 mackerel taken. 



In order to ascertain whether the temperature of the water during 

 the fishing months in the different years bore any relation to the takes 

 of mackerel, and to meet the suggestion that the effect of the bright 

 sunshine might have been simply to increase that temperature, a series 

 of curves have been drawn showing the average temperature of the 

 surface water in February, March, April, and May for each of the years 

 1902-1908 in the area between 48° and 50° North Latitude and 4° 

 and 10° West Longitude. The temperatures given in Table VI., and 



