INVESTIGATIONS IN FORTH, SUMMARY. 183 



immaterial whether we take the closed or open areas separately, 

 as in the Report, or group them together, as in the present 

 case (Tables XI. and XII.). In the comparison of the captures 

 of the flat fishes in the closed and open areas the same misap- 

 prehension is made, the difference of 100 per haul readily falling 

 to 1887 with its working period confined to the three pro- 

 ductive summer months. In like manner the notion that on 

 the cessation of trawling there appears to have been an increase 

 in the abundance of fishes within the closed areas, " as shown 

 by the high averages in the year 1887^" must lapse. The 

 choice of 1892 for a low average of flat fishes in St Andrews 

 Bay is in the same category, for while in that year 16 hauls 

 occurred in the moderately productive months of May, June, 

 and October (July, August, and September with their high 

 figures being blank), no less than 28 hauls were in the colder 

 months of February, March, April, November, and December. 

 Fluctuations in these and similar cases are due to other causes 

 than a dearth of fishes. In the Report, however, it is pointed 

 out that the curve of fluctuation in the abundance of round and 

 flat fishes corresponds with the general curve for the food-fishes, 

 a conclusion which is in accordance with the method adopted 

 here, viz., dealing with the subject as a whole. From the 

 figures in the Report it would appear that in contrasting 

 the two periods of five years there was an increase of fishes of 

 all kinds in the closed area of the Forth from 242 to 252, or 10 

 per haul; moreover, that there was an increase in the open area 

 from 160 to I7l, or 11 per haul. In this total the flat fishes 

 showed very little change, a diminution of 2 in the closed and 

 1 in the open only occurring between the first five years and 

 the second. But, on a consideration of the circumstances 

 attending the work of the two periods, it would seem that this 

 diminution might well have been larger, since of a total of 

 269 hauls no less than 159 occurred in the warmer months 

 (May to October), as against 110 in the colder. Fifty hauls in 

 favour of the warmer period is a very considerable advantage, 

 and it would not be unfair to conclude that if the proportions 

 of the warmer and colder periods in the first five years had 

 1 Uth Report S. F. B. p. 148. 



