48 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



The movements ami migrations of fish are of two classes; the one 

 irregular and occasional, the other regular. The irregular migrations 

 are such as occur only at long intervals, sometimes altering very ma- 

 terially the industrial and social conditions of maritime countries. 



Among the most notable illustrations of irregular migrations, we may 

 cite the case of the bluefish, which during the past century w r as a well- 

 known inhabitant of the eastern coast of the United States, occurring 

 in great abundance and of large size. This species appears regularly 

 on our eastern coast in the spring and leaves in autumn ; but some 

 time after the middle of the last century it disappeared entirely, ac- 

 cording to the histories of the time, and was not seen during the present 

 century until much of it had passed by, having been absent for a period 

 of about fifty years. Of course it is possible that it may have occurred 

 in small numbers, but not sufficient to make any impression ; at any 

 rate, on its reappearance in 1825 or 1830 it was entirely new to all the 

 fishermen. 



Another case is that of the chub mackerel (Scomber pneumatophorus). 

 This, twenty years ago, was extremely abundant and was taken in large 

 numbers at the same time with the common mackerel; but of which 

 in later years only occasionally individuals have been captured. 1 

 have succeeded in securing only one or two specimens since the com- 

 mencement of the operations of the United States Fish Commission, 

 although every effort has been made to obtain them. 



A European member of the mackerel family is extremely capricious 

 in its movements. It is the Caranx traehurus, or the scad, a well-known 

 fish of the Mediterranean and of the European coast generally. This 

 sometimes sweeps down in immense numbers upon the shores of regions 

 where it was previously unknown, or where it has not been seen for 

 many years ; a notable instance of this occurring in 1862, when im- 

 mense numbers made their appearance on the coast of Bergen and in 

 the Shrange Fiord, furnishing occupation in their capture and prepara- 

 tion to a large population ; but scarcely was it at all known except in 

 straggling specimens before or since.* 



The causes of these variations in distribution are entirely unknown ; 

 whether the fish have been exterminated by some disease or pestilence 

 (as suggested in the case of the bluefish), &c, cannot be ascertained. 

 Various changes in the number of herring on the coast of Northern 

 Europe have been of a similar character. These have been more espe- 

 cially important as influencing the condition of the population of Norway 

 and Sweden and other northern countries. On the coast of Sweden her- 

 ring were formerly in enormous abundance, sustaining a large popula- 

 tion along the shores, but have disappeared for decades. It is with the 

 regular migrations of the fishes of our coast that we have at present most 

 to do, and I shall proceed to consider them under several headings. 



Baars, Dcs Fisehereiu Industrie cle la Norw<3ge, 1873 ; p. 158, 



