200 BULLETIN OF THE BUREAU OF FISHERIES 



accounting for the young "tinkers" reported in 1912. The j-ears 1913 and 1914 

 must have been still more productive to produce the great preponderance of the 

 "small" class in 1914 and 1915; and 1914 may also have been a good breeding season, 

 for with so loose a classification (no subdivision of the fish smaller than 13^ pounds) 

 it is impossible to tell how many fish become marketable in their second summer and 

 how many not until their third summer. The total catch was more than 50 per 

 cent greater in weight in 1916 than in 1915, but this increase was due chiefly to the 

 graduation of fish that were " small " in 1915 into the " medium " and "large" classes, 

 which together increased from about 14 per cent of the total weight caught in 1915 

 to about 80 per cent in 1916, and which probably dominated the catch in actual 

 numbers as well, while the "small" fish formed less than 20 per cent by weight. 



Small fish were again more abundant in 1917 than in 1916, both by weight 

 (34 per cent of the catch) and probably in numbers, pointing to a very considerable 

 production either in 1915 or in 1916, whichever of these two-year classes was con- 

 cerned ; but for several years thereafter breeding was so unsuccessful that the number 

 of mackerel in such part of the stock as is tapped by the Gulf of Maine fishery dwin- 

 dled from year to year as the year classes produced during the period 1912 to 1914 

 died out from one cause or another, without a sufficient production of young to com- 

 pensate for the death rate, resulting in the great decline in the fishery noted above 

 (p. 199), though enough yoimg survived to keep the relative proportions of large and 

 small fish about constant until 1919. Either in 1918 or in 1919 reproduction 

 must have been close to a total failure, for the mackerel caught in and off the Gulf 

 of Maine in 1920 ran very large, with small fish composing hardly 6 per cent (by 

 weight) and large fish more than 60 per cent of the catch. The mackerel caught 

 south of New York during that spring likewise averaged about 2 pounds in weight. 



As regards its composition, the stock was now back again in about the same state 

 as in 1910, the cycle having run over a period of 10 years. The parallel goes still 

 further, too, for while no precise data as to sizes of the mackerel are available for 

 1921, that year must have seen a wave of production comparable to the successful 

 breeding of the period of 1911-1914 to account for the swarms of yearling fish that 

 appeared along the New England coast from Woods Hole to Mount Desert during 

 the summer of 1922. Past experience would suggest that this presaged a great 

 increase in the catch of mackerel for the next few years to come, as these little fish 

 grow into the medium and large classes; and so it proved, for in 1923 over 11,000,000 

 pounds were taken in the Gulf of Maine region alone, and more than 8,000,000 

 pounds of this catch close alongshore. 



Thus it seems that the proportion of large and small fish and the size of the catch 

 for any one year may be used as a basis for predicting the success or failure of the 

 run of mackerel in the following year. There may also be several good breeding 

 years in succession, but history also teaches that after the fish of the 1921 year 

 class and of the next two or three following (should there be more than one year of 

 great production), pass their zenith and begin to drop out we must once more look 

 forward to a shrinkage in the stock of mackerel and to poor fishing, for as far back 

 as the record runs a good breeding year or a succession of such has been rather a rare 

 event. 



