D'ARCY W. THOMPSON 



Let US now proceed to inspect tlie average catches of Cod and Codling month by 

 month in each separate area, commencing with those areas for which we have the best 

 and most ample information. We can best examine and compare our statistical data by 

 drawing them in the form of curves, as has been already explained in the introduction 

 to our statistics published in a former volume. The curves are easily drawn from the 

 figures given in the tables, and we must be content to illustrate them in limited number'. 



Fig. 5 shown the successive monthly averages of Cod (as usual, in cwts. per lOO 

 hours' fishing) for area XXIX, oft" the east coast of Scotland, south of Aberdeen and 

 westward to the meridian of o°. The statistics are complete, save for a slight break in 

 the beginning of 1902. 



It will be seen at a glance that the seasonal fluctuations recur from year to year 

 with remarkable regularity. Year by year the maximum is attained about March or 

 April, and year by year the minimum is reached in October or November; there is no 

 striking diff"erence between one year and another in regard to this seasonal phenomenon. 

 It is in the next place evident that there has been no such thing as a decrease of Cod 



1901 



1902 



1903 



190^ 



1905 



1906 



Fig. 5. Cod. Area XXIX. 



upon this area from year to year. The highest maximum, it is true, is apparently that 

 of 1902, but so is the lowest minimum: and for the last three years the curve is re- 

 markably uniform, with apparently a very slight rise of maximum and latterly a fall of 

 minimum from year to year. 



The next figure shows a similar curve for Codling on the same area. It is not 

 quite so regular as the curve for Cod; but nevertheless it shows on the whole the steady 

 recurrence of an annual wave, with a winter maximum in (or within a month of) Dec- 

 ember, and a spring or summer minimum that comes within a month or two of May. 

 A slight peculiarity is to be noticed in 1903, in which year the Codhng were less scarce 



I The curves here drawn have been in all cases (unless it is otherwise stated) drawn not directly 

 from the monthly averages recorded in the Tables, but have been smoothed by combining with each 

 monthly average that for the immediately preceding and following months. The point on the curve 

 corresponding, for instance, to February of a particular year represents the mean of the average catches 

 for January, February and March, In the drawings the space occupied by each year is divided into twelve 

 columns for the respective months. 



