904 



REPORT — 1898. 



possession of characteristics which are just the reverse of those which distinguish 

 the North Sea and Channel fish. 



It would appear from these results that we have two races of mackerel on the 

 English coasts — an Irish or Atlantic race, and a race which frequents the English 

 Channel and the North Sea. 



The fish taken oiF Scilly and Brest offer characteristics which are in several 

 respects intermediate between the two principal races here distinguished, but 

 the numbers examined up to the present time are not sufficient to enable me to 

 decide upon their relationships in a definite manner. 



If these results be accepted or confirmed, the problems of the migrations of the 

 mackerel and of its winter home are considerably simplified. The Irish fish in 

 winter must remain off their own coasts, or they would lose their peculiarities by 

 mixture with other races. The North Sea and Channel fish probably have the 

 same wdnter haunts off the mouth of the English Channel — not too far to the west- 

 ward, or they would mix with the Irish fish. That the North Sea fish migrate 

 into the Channel in winter is rendered probable by the enormous concentration of 

 mackerel in the southern part of the North Sea in autumn, and by the prolonga- 

 tion of the mackerel fishery far into the winter off the Devon and Cornish coasts 

 of the Channel, long after the fish have disappeared from the North Sea and the 

 Irish coasts alike. 



A complete account of this investigation, with tables showing the variation of 

 each character, will appear in the forthcoming number of the * Journal of the 

 Marine Biological Association.' 



Summary showing Deviations from the General Mean in respect of all 



Characters. 



* These Means were derived from a total number of fish less by 99 than the 

 number stated in the first column in each case. 



