16 XIIE IMPOVERISHMENT OF THE SEA. 



maintains its greater productivity for the same number of months as 

 for plaice alone. 



Of the months* in which the influence of St. Andrews Bay on the 

 averages is greater for the second period than for the first, it will be 

 noticed that February is one of the three exceptional months in which 

 plaice and lemon soles are less abundant in the Bay than in the Forth. 

 Consequently, the fall in the combined average catch of these fishes, 

 when the two periods are compared, is again explicable merely from the 

 fallacy latent in the disproportionate combination of the statistics of 

 the t'.YO areas. The July averages are exceptional in showing an 

 increased catch in the second period compared with the first. This 

 feature also may be directly attributed to the increased influence of the 

 Bay in the second period. In November alone is the verdict of the 

 averages at variance with the tendency caused by the increased 

 influence of the Bay during the second period — an exception which 

 can be conclusively traced to an altogether exceptional catch of plaice 

 in St. Andrews Bay in 1889. The average haul of plaice in November, 

 1889, in the Bay, amounted to 213 fishes. The average for the four 

 other years during which surveys were made in the same month were 

 38, 47, IG, and 10 respectively, and only one of these fell in the first 

 quinquennial period. Had observations been also made in the five 

 remaining years, no doubt the abnormal difference in the averages for 

 the two periods caused by the exceptional catch just mentioned would 

 have been reduced to juster proportions. 



There is, therefore, no escape from the conclusion that the comlination 

 of the figures for the Forth and the Bay is sufilcient mi itself to accoiint 

 for decreased averages for plaice and lemon soles in the second period as 

 comjjarcd ivith the first. 



As regards the reported increase of dabs and long rough dabs, the 

 same argument holds to a considerable extent. It has already been 

 pointed out that the disproportion between the Bay and the Forth is 

 less in the case of dabs than in the case of plaice. This is particularly 

 so if dabs and long rough dabs are grouped together, since the scarcity 

 of the latter in the Bay, and their relatively large numbers in the 

 Forth, greatly reduce the difference which exists between the two areas 

 in regard to the relative abundance of common dabs alone. It can be 

 seen from Table I. that in the closed waters dabs and long rough dabs 

 together are more numerous in the Forth than in the Bay in January, 

 February, March, April, July, and December. There can be no doubt, 

 as previously remarked, that the July figures for St. Andrews Bay can- 

 not be regarded as strictly accurate, owing to the inadequate number of 

 observations ; but the fact remains that, under the conditions of the 



* February, July, and November. 



