of the Fishery Board for Scotland. 



Ixiii 



stations of the " Garland" in the Moray Firth and the Firth of Forth. 

 These hauls were made with the same apparatus as was formerly 

 used by the " Garland," and as the investigations of that vessel were 

 begun as long ago as 1886, and were continued until 1896 in the Firth 

 of Forth, and until 1900 in the Moray Firth, comparison of the results 

 with reference to the relative abundance of the various species of 

 food-fishes at the different periods will be of interest and value. A 

 paper dealing with the more important results of the earlier investi- ' 

 gations of the " Garland " was published in Part III. of the Board's 

 Fourteenth Annual Report. 



Marking Experiments. 



The number of food-fishes which were "marked" and liberated in 

 1911 by the "Goldseeker" amounted to 2267, comprising the follow- 

 ing species : — Plaice, 1733 ; haddock, 225 ; cod, 52 ; witch, 126 ; lemon 

 dab, 111 ; megrim, 6; flounder, 4; brill, 8 ; dab, 2. It will be seen 

 that, as in former years, efforts were chiefly concentrated on the 

 marking of the plaice. This is because it is the fish which is the most 

 immediately important in connection with the international investi- 

 gations, and it is the one best adapted for this particular method of 

 research. It was desired that the same system should be applied to 

 the haddock, but it was found that this fish is very easily injured by 

 the handling and the process of marking, and none of the 225 which 

 were marked at various times and places was recovered. The same is 

 true of the witch, and to a great extent of the lemon dab, as was 

 ascertained by keeping the fishes, after the mark had been fixed on, 

 for some time in tubs of running water, most of them dying sooner or 

 later. Of the plaice which were marked, on the other hand, 461, or 

 over 26 per cent., were re-captured in the course of the year, and up 

 to the end of March 1912. The mark consists of a numbered vulcanite 

 disc, attached to the fish by means of a silver wire, or of a vulcanite 

 stud fixed in place by a rubber ring. 



The main objects of the marking experiments are to ascertain (1) 

 the migrations of the fish ; (2) their growth ; (3) the intensity with 

 which fishing operations are carried on. For any of these purposes it 

 is necessary that some time should elapse in order that a sufficient 

 amount of evidence may be accumulated for the formulation of satis- 

 factory conclusions. There are some results, however, to which 

 attention may be meanwhile directed. The first relates to the 

 migrations of the plaice. In 1910 the number of marked plaice which 

 were liberated was 1915, and of these no less than 866, or over 42 per 

 cent., have been recaptured, and others will doubtless be taken as 

 time goes on. It has been found, with reference to their movements, 

 that a distinction mast be drawn between those which have not 

 reached the size of maturity and those which exceed that size. The 

 former do not, as a rule, move far from their ordinary feeding grounds, 

 and they do not appear to take any very definite direction in such 

 movements as they make ; the latter, on the other hand, undertake 

 often long journeys before the spawning season, and in the great 

 majority of instances they move along the East Coast in a northerly 

 direction, that is to say, against the prevailing current. This migra- 

 tion is doubtless to compensate for the southerly drift of the floating 



