FISHES OF THE GULF OF MAINE 



327 



northern, with rather different migratory habits, 

 and differing also in the relative success of repro- 

 duction in different years. 47 The nature of these 

 two contingents is not known, whether genetic or 

 environmental. 



It is probable (though not proved) that the 

 southern contingent tend to winter in the southern 

 part of the wintering zone. The main bodies of 

 mackerel that appear in spring along the middle 

 Atlantic coast belong to this contingent, also most 

 of those taken off southern New England. They 

 summer for the most part over Nantucket Shoals; 

 on the western part of Georges Bank; and in the 

 western and northwestern parts of the Gulf of 

 Maine, which they enter in the western side around 

 Cape Cod. And they do not journey farther east 

 than the coast of Maine. On the other hand, it 

 seems the mackerel that appear early in the season 

 along the Nova Scotian shore of the Gulf, to 

 spread later to Maine, belong to the northern 

 contingent, and also a scattering of those that 

 enter the western side of the Gulf. These appear 

 to winter mostly eastward from the Hudson 

 Gorge, and their vernal migration carries most of 

 them past our Gulf, to pass the summer along 

 outer Nova Scotia, and in the southern side of 

 the Gulf of St. Lawrence. 48 



A few mackerel (mostly small) from the southern 

 contingent remain all summer in the coastwise 

 belt from Long Island to Nantucket. Apart from 

 these, however, the whole body of American 

 mackerel have deserted the southern grounds 

 altogether by the early summer, to spend the 

 later summer either in the region of our Gulf, off 

 Nova Scotia, or in the Gulf of St. Lawrence. 49 



If the view now held is correct as to their 

 migratory routes, some of the mackerel that sum- 

 mer in our Gulf may come from as far as the offing 

 of North Carolina; others from as nearby as the 

 offing of New York or of southern New England. 

 The vernal journey of the Gulf of St. Lawrence 



•' This conclusion, seemingly conclusive, is based on analysis of the size 

 (i.e. age) composition of the mackerel population at various times and places, 

 with some evidence from tagging experiments. The data are too extensive 

 for discussion here. 



< ! For further Information as to migrations of the northern contingent, see 

 Sette, Fish. Bull. U. S. Fish and Wildlife Service, vol. 51, Bull. 49, 1950, 

 pp. 269, 285. 



« We have found no positive record of mackerel taken in late summer 

 anywhere south of Delaware Bay, although they are plentiful off this part of 

 the coast In spring. Bell and Nichols, it Is true, speak of "mackerel" as 

 found In tiger-shark stomachs oft North Carolina (Copela, No. 92, 1921, pp. 

 18-19), but Dr. Nichols writes us that these were "just Scombroids and 

 probably not Scomber scombrua." 



mackerel may be anywhere between, say 300 to 

 350 miles, and 700 miles, depending on whether 

 they have wintered off outer Nova Scotia or as 

 far west as the western slope of Georges Bank. 



It seems certain that some of the mackerel that 

 are first sighted on Nantucket Shoals and on 

 Georges Bank in May remain on these offshore 

 grounds all summer, both spawning and feeding 

 there, for they provide good fishing there any time 

 from June to September or October, in some years. 

 The farther advance of such of them as continue 

 northward into the Gulf of Maine covers a period 

 of some weeks, with the first-comers followed by 

 other schools later. And it seems certain (as 

 just remarked) that fish resorting to our Gulf, do 

 so summer after summer, never visiting the outer 

 coast of Nova Scotia, much less a region as far 

 afield as the Gulf of St. Lawrence. But it is an 

 interesting question for the future, whether a 

 given school returns to the same part of the Gulf, 

 year after year. 



Many of the mackerel that summer in our Gulf 

 have already spawned farther south (p. 322). 

 Others, however, are still hard, but they are soon 

 taken there with eggs or milt running. Spawning 

 in the Gulf of Maine is at its peak in June in most 

 years, with the proportion of spent fish increasing 

 through July, and only an occasional ripe fish as 

 late as the first of August. But a year comes occa- 

 sionally, such as 1882, when spawning is not at its 

 height in the Gulf until July, with ripe fish con- 

 tinuing plentiful until August. And our towings 

 there have yielded a few mackerel eggs as early as 

 May 6, as late as September l. 60 



The spawning season is at its height in the Gulf 

 of St. Lawrence during the last half of June and 

 the first half of July, continuing into August, a 

 fact well known by the hook-and-line fishermen of 

 half a century ago, because the ripe fish will not 

 bite at that time, and more recently corroborated 

 by the egg catches of the Canadian Fisheries 

 Expedition. 61 



It seems from the relative numbers of eggs taken 

 from place to place, that Cape Cod Bay is the only 

 subdivision of our Gulf that has rivaled the more 

 southern spawning grounds in egg production dur- 

 ing the particular years when intensive studies 



» See Bigelow and Welsh (Bull. U. S. Bur. Fish., vol. 40, Pt. 1, 1925, p. 

 206), for details. 

 « Dannevlg, Canadian Fish. Exped. (1914-1915); 1919, p. 8. 



