of the Fishery Board for Scotland. 



Ixiii 



national Council at their last meeting reached certain conclusions 

 with regard to the plaice fishery in the North Sea, it has been decided 

 to discontinue them in the meantime. The particulars in regard to the 

 plaice marked in each of the ten years, and the percentage of recaptures 

 are as follows : — 





Number 



Number 



Percentage 



Year. 



TjibpTfi tpfl 



T?,pp,f),'ntn Tpn 



T^prantured 



1904 . 



310 



101 



32-6 



1905 . 



245 



89 



36-4 



1906 . 



40 



12 



(30-0) 



1907 . 



13 



6 



(46-1) 



1908 . 



259 



67 



25-9 



1909 . 



336 



65 



19-3 



1910 . 



. 1915 



986 



51-5 



1911 . 



. 1733 



864 



49-9 



1912 . 



. 2165 



1018 



47-0 



1913 . 



. 1345 



303 



22-5 





8361 



3511 



42-0 



It will be observed that the percentage of recaptures varies some- 

 what, the mean for the ten years (at the end of 1913) being 42. But as 

 many of the marked fishes liberated in any one year are taken in suc- 

 ceeding years — it may be for four or five years — the percentage of 

 recaptures will be yet increased. Of the 1915 plaice marked and 

 liberated in 1910 over half were again taken by fishermen, and mostly 

 by trawlers. The results of some particular experiments give a much 

 higher percentage even than that. A report on the results of the 

 marking experiments from 1904 to 1909 was published last year, and a 

 final report is now being completed. 



With reference to the movements of the marked plaice it may be 

 said that a distinction must 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 migration is doubtless to compensate for the southerly drift of 

 the floating eggs and larval fishes from the localities where spawning 

 takes place. Thus many of the adult plaice which had been marked 

 and liberated in the Firth of Forth, or eastwards of the Isle of May, 

 were recaptured ofi the coast of Aberdeenshire, or in the Moray Firth ; 

 many of those liberated off the coast of Aberdeenshire were again 

 taken in the Moray Firth, or on the North or West Coast, having in 

 such cases traversed the Pentland Firth. In like manner many of 

 the adult plaice liberated in the Moray Firth, or in the vicinity of 

 Fair Isle, were recaptured at the Orkney Isles, or on the North Coast 

 and the West Coast. It is interesting to have determined that the 

 plaice in the Moray Firth are recruited to such an extent from the 

 grounds off the East Coast, and even from the Firth of Forth, by the 

 migration thither of the adult fish. It is also fairly certain, though 



