198 BULLETIN OF THE BUREAU OF FISHERIES 



on the bottom on the continental slope, vernal changes in the temperature of the 

 surface water would be quite outside their ken. In short, the precise stimulus 

 causing them to rise to the surface then is still to be learned. 



Fluctuations in ahundance. — It has been a matter of common knowledge since 

 early colonial days that mackerel fluctuate widely in abundance from year to year — 

 perhaps more so than any of the other important food fishes — periods of great 

 abundance alternating with terms of scarcity or almost total absence, a serious 

 matter for the fishermen. During good 3-ears the fish may appear in numbers 

 almost unbelievable — schools or associations of schools, miles in length, are reported. 

 It is common to see 50 or more separate bodies of fish from the masthead at one time. 

 Mackerel, in short, seem to be everywhere, and a tremendous catch is made; but 

 perhaps the very next year, and for no apparent reason, only an odd school will be 

 found here and there and the fishery is a flat failure. 



Looking back over the published statistics we see that from 1825 to 1835 was 

 a period of abundance. In 1S31, for example, more than 380,000 barrels (76,000,000 

 pounds) of salt mackerel (in those days most of them were salted) were landed in 

 Massachusetts ports alone. Then for the next eight years (1837-1845) mackerel 

 were scarce, only 50,000 barrels being landed in Massachusetts in 1840. From 1851, 

 when the Massachusetts landings rose once more to 348,000 barrels, down to 1879, 

 the annual catch fluctuated violently; but the year 1880, when the fleet brought in 

 something like 294,000,000 fish from Nova Scotian and United States waters com- 

 bined, saw the inception of a period of extraordinary abundance, culminating in 

 1885 when the catch reached the enormous total of 500,000 barrels (100,000,000 

 pounds). This was followed by a decline so extreme, so widespread, and so calami- 

 tous to the fishing interests that when the stock of mackerel reached its lowest ebb 

 in 1910 the catch of the American mackerel fleet was only about 3,400 barrels 

 (equivalent to 582,800 pounds of fresh fish) for the entire coast of the United States, 

 with almost no mackerel, large or small, reported in Massachusetts Baj* or along 

 the Maine coast. As previous experience suggested, however, mackerel then 

 increased once more in numbers, as appears from the annual catches made in the 

 Gulf of Maine and on the banks at its mouth. 



Year Pounds 1B 



1910 574,092 



1911 2,478,331 



1912 4,366,906 



1913 4,777,442 



1914 7,506, S75 



1915 11, 106,095 



1916.... 16,391,377 



1917 16,021,619 



1919 2,344,552 



1920" 5,608, 157 



1921 1, 029, 002 



1922 r 3,048, 071 



1923.. 11,007,676 



" Salt mackerel are here reduced to the equivalent weight of fresh fish; no data are available for 1918. 



* T The southern fishery reported a good catch in 1920, which was not reflected either in the Gulf of Maine or in Nova Scotian 

 waters. 



