62 THE IMPOVERISHMENT OF THE SEA. 



Accordingly, from the data available, I can discover no error of 

 sufficient magnitude to account for the yearly decline in the average 

 catches which my table reveals. The discrepancy between my esti- 

 mated averages for 1889 and 1890 and the actual averages of Mr. 

 Alward's smacks for the same years should probably be attributed to 

 the incidental differences which cannot fail to manifest themselves 

 between the averages of a few sailing vessels working upon a small 

 portion of the field and the averages derived from all boats over the 

 entire North Sea area. The difference between the averages of the 

 Grimsby and Lowestoft smacks in 1892 is sufficient to indicate the ex- 

 tent of the variations which must be expected in any year in the 

 catches of sailing vessels working upon different and limited grounds. 

 The catches of sailing vessels cannot, of course, do more than indicate 

 the fluctuations in the fishery on the grounds frequented by the vessels. 

 My estimated averages, however, profess to indicate the relative fluctua- 

 tions in the fishery over the entire region of the North Sea visited by 

 steamers and smacks alike. 



Owing to the fact that the catch per unit was assumed to have been 

 961 cwts. ( = 48 tons) in 1885, my figures would appear to indicate that 

 between that year and 1889 a rise took place in the general averages, 

 possibly in consequence of the exploitation of new grounds by the 

 steamers. It is of course perfectly possible that the amount of this 

 rise has been exaggerated by the mode of determination adopted in this 

 essay and by the multiplication of small errors in the assumptions 

 which have been made. To this I can only reply that it is improbable 

 that irregularities of this kind should affect the figures in the same 

 direction throughout the decade, especially when every precaution has 

 been taken under each item in the calculations to prefer such alterna- 

 tives (where any choice was presented) as would prevent under- 

 estimation of the catching power in the earlier years and exaggeration 

 of the same in the later years of the decade. 



But in regard to the averages for the South and West Coasts, the 

 figures which represent them are so far below the actual catches of the 

 Grimsby smacks at the beginning of the period, and yet are so uniform 

 throughout the whole period, that I cannot place the same confidence in 

 the results. It has already been pointed out that an exceptional diffi- 

 culty occurs in regard to this area in consequence of the number of 

 North Sea vessels which have visited these waters during the period 

 under consideration, and the probability that the numbers which I have 

 assigned to them are excessive both in consequence of the method of 

 determination and of the uncertainty as to the length of their sojourn. 

 The extent of the error introduced from this source may best be 

 determined by comparing the averages in Table VIII. (p. 34) with the 



