642 REPORT— 1902. 



let. It is shown that the analysis of the Frith of Forth investigations published 

 in the Sixteenth Annual Report of the Inspector of Fisheries (' Sea Fisheries : 

 England and Wales ') indicates that the results as to the number and size of fish 

 captured in auy one area may diverge widely from those obtained in closely adja- 

 cent areas. It would thus appear that it is fallacious to draw conclusions from 

 such small samples as can be procured by the method to be adopted in the proposed 

 scheme. 



2nd. It is pointed out that the take per capturing unit varies with the number 

 of capturing units at work as well as with the density of the fish, and that, there- 

 fore, it is fallacious to accept it as a measure of the latter. This is illustrated by 

 the example of the effect of increasing the number of bag nets in a range of nets 

 on the take of salmon per net. It is pointed out that the majority of the Norwe- 

 gian Commission on Salmon Fisheries fell into this error of accepting the take 

 per net as a measure of the abundance of salmon, and that Mr. Garstang, in his 

 ' Impoverishment of the Sea,' also made the same mistake. His Grimsby figures 

 are analysed, and it is shown that they do not justify his conclusion that a 

 decrease in the number of fish is proved by them. It would therefore appear that 

 to accept the take per unit as a measure of the abundance of fish is fallacious and 

 likely to yield unreliable results. 



The danger of allowing international investigations, which may be expected to 

 lead to legislation for the regulation of our fisheries, to be carried out by such 

 unsatisfactory methods is strongly urged. 



4. The Scales of Fishes as an Index of Age.^ By J. Stuart Thomson. 



This paper took the form of a lantern demonstration illustrating the new method 

 of determining the age of Gadoid fishes by means of their scales. 



The scales of Gadoid and many other fishes show a series of parallel eccentric 

 lines which indicate successive increments of growth. These lines of growth have 

 been found to be more widely separated in that part of the scale formed during the 

 warm season of the year than in the portion formed during the cold season ; the 

 alternation of the two series gives rise to the appearance of ' annual rings ' which 

 indicate the age of the fish in years. 



5. lieport on the Migration of Birds. — See Reports, p. 273. 



6. Report on the Occupation of a Table at the Zoological Station, Naples. 



See Reports, p. 259. 



7. Report on the OccujMtion of a Table at the Marine Biological 

 Laboratory, Plymouth.- — See Reports, p. 271. 



8. Report on the ' Index Animalirim.' — See Reports, p. 283. 



9. Twelfth Report on the Zoology of the Sandwich Islands. 

 See Reports, p. 284. 



' The paper will be published in extenso in the Journal of tlie Marine Biological 

 Association. 



