324 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



FLUCTUATIONS IN MACKEREL 



Landings of mackerel on the east coast of the 

 United States from 1804 to 1930 have been esti- 

 mated by Sette and Needier (1934). Their esti- 

 mates for the period 1804-81 are based on records 

 of inspection of barrels of mackerel in Massachu- 

 setts (Goode et al., 1884). Landings for the 

 period 1878 to 1904 were available from the re- 

 ports of the Boston Fish Bureau. Since 1893, 

 landings at the principal New England ports have 

 been published by the United States Bureau of 

 Fisheries and its successor, the Fish and Wildhfe 

 Service. Except for the period 1804 to about 

 1820 when the fishery was beginning, the fluctua- 

 tions in catch appear to reflect fluctuations in the 

 abundance of mackerel. 



In figure 19, landings of mackerel are plotted 

 against annual deviations in air temperature at 

 New Haven that occurred 3 years earlier than the 

 landings. Both curves are smoothed by 5-year 

 moving averages. There is a marked tendency 

 for rising temperatures to be associated with good 

 catches 3 years later, the reverse with falling 

 temperatures. 



From 1820 to 1890, four major peaks occurred 

 in mackerel landings, each associated with a 

 period of higher temperature. The degree of asso- 

 ciation of landings with temperature may be de- 

 termined by correlating the unsmoothed data, 

 that is, correlating the landings in an individual 

 year with the annual temperature deviation oc- 

 curring 3 years earher. When this is done, the 

 highly significant correlation coefficient of 0.554 

 is obtained for the 71-year period. Since air tem- 

 peratures are not perfectly correlated with water 

 temperatures and since it is the actual water tem- 

 perature which may be expected to influence the 

 mackerel, possibly a much higher correlation 

 would be obtained if water temperatures were 

 available. 



Following the high point reached in mackerel 

 landings during the 1880's the catch dechned rap- 

 idly and has never since reached its former high 

 levels. From 1820 to 1890 the average annual 

 catch was about 89 million pounds; between 1891 

 and 1950 it was about 33 million pounds. We see 

 nothing in the tempera.ture record to account for 

 this change in abundance, although the former 



1807 



1827 



YEAR- (TEMPERATURES) 

 J8.47 1867 1887 



1907 



1927 



1947 



1800 1820 1840 I860 1880 1900 



YEAR (LANDINGS) 



1920 



19 40 



Figure 19.— Landings of mackerel, 1804-1950, in New England (solid line) compared with annual deviations in air 

 temperatures at New Haven, Conn., occurring 3 years earlier than the landings. (The curves are smoothed by 5-year 

 moving averages.) 



