PROGRESS IN BIOLOGICAL INQUIRIES, 192 7 209 



the intensive and abusive fishery each year must prevent many fish 

 from breeding. During the session of the Maine Legislature last 

 winter an effort was made to secure the passage of a bill providing 

 adequate protection for the smelts of Maine in the fresh-water por- 

 tions of brooks frequented by salt-water smelt for breeding, a thmg 

 which they never have had. The. bill did not reach the committee, 

 although it was approved and recommended by the United States 

 Commissioner of Fisheries. 



MACKEREL 



During 1927 the investigations on the mackerel fishery, in coopera- 

 tion with the division of fishery industries, were continued by O. E. 

 Sette, assisted by E. W. Bailey. R. A. Nesbit, R. A. Goffin, and 

 Thomas Quast also were engaged on this investigation during the 

 season. As in the previous year, the program consisted principally 

 of the simultaneous collection of biological and statistical data on the 

 mackerel fishery to provide information as to the life history of the 

 species, the fluctuations in abundance, and the cause of such fluctua- 

 tions. 



During the 1927 season observers were stationed in the principal 

 mackerel-receiving ports, where they interviewed the vessel fisher- 

 men and secured data on locality, dates, and size of catch, and meas- 

 urements of samples of the mackerel landed. During this period 

 1,181 trips of mackerel seiners were recorded and samples from 1,135 

 of these w<ire measured. This constituted catch data on approxi- 

 mately 75 per cent of the quantity of mackerel landed and measure- 

 ments of samples from 74 per cent. Similar data were collected from 

 the mackerel netters. In all, 36,263 measurements were made and 

 scales were collected from 2,898 specimens. 



An incomplete analysis of the 1927 data indicates that during the 

 past season the mackerel of the 1923 year class continued dominant 

 in the catches. This is the third season in which this dominance has 

 been well marked, leading to the conclusion that spawning seasons 

 since 1923 so far have failed to produce sufficient mackerel to make 

 an appreciable showing in the commercial catch. Also, the 1923 age 

 group is beginning to decline in abundance, as indicated by a slightly 

 smaller catch in 1927, the decrease, compared with 1926, being ap- 

 proximately 12 per cent. Thus this investigation is providing an 

 accumulation of information as to the number of years in which good 

 catches may be made of the offspring of an unusually good year class, 

 and by collecting this information we are beginning to understand 

 the effects on the commercial fishery of unequal birth rates from year 

 to year and the mortality in subsequent years. 



The steamer Alhatross II was detailed to the mackerel work for 

 about two weeks in May and was engaged in making tow-net hauls 

 and taking other oceanographic data along the coast between Cape 

 May and Cape Cod. Forty-one stations, distributed on the conti- 

 nental shelf between the coast and the 1,000-fathom contour, were 

 visited. Remarkably good catches of mackerel eggs and larvae were 

 made at virtually all stations. The greatest concentration was found 

 between the 20 and 40 fathom contours and in the area off New 

 Jersey and Long Island. The greatest number of mackerel eggs 



