FISHES OF THE GULF OF MAINE 197 



Channel, but most of them, as appears from the statistics of the fishery, to go still 

 farther out, probably to the outer edge of the continental shelf off Ireland to pass 

 the cold season in deeper water. 43 



On this basis we might expect the Gulf of Maine mackerel to winter on the 

 upper part of the continental slope at a depth rather greater than the otter trawlers 

 reach — say at 100 to 200 fathoms — but so close at hand that odd fish stray or remain 

 on the banks. Two facts strongly support the view that they go no farther than 

 this in their offshore migration. First, no mackerel, young or old, have ever been 

 taken far outside the continental shelf by the various deep-sea exploring expeditions 

 of the past half century, or for that matter anywhere on the high seas far from land, 

 nor more than a few miles south of Cape Hatteras off the American coast. Second, 

 their reappearance takes place so nearly simultaneously in spring along many 

 hundred miles of coast line that they can hardly have come from any great distance. 

 It may be that some mackerel regularly winter in the deep basin of the Gulf of 

 Maine itself. The winter catches listed above do, in fact, suggest that such is the 

 case, and while as yet no direct evidence has been obtained that this applies to 

 any considerable body of fish, the ground in question offers an attractive field for 

 investigation with the otter trawl with an eye to the possibility of developing a 

 winter fishery for mackerel. Thus time and increased knowledge have corroborated 

 the views of Captain Atwood and of Perley, of more than half a century ago, that 

 mackerel winter offshore in deep water and northward from the latitude of Virginia, 

 not in the far south nor out in the surface waters of the warm parts of the Atlantic. 



It has often been argued that mackerel hibernate. We even have the positive 

 story of an " eyewitness " of high rank — an admiral, no less — of thousands so reposing 

 in the mud in the Bays of Greenland with tails protruding — wholly an imaginary 

 tale, we need hardly add. 44 Equally baseless, too, is the oft-repeated assertion 

 that the adipose eyelid becomes opaque, so predisposing to hibernation in winter. 

 European mackerel may sometimes hibernate. Ehrenbaum, 45 whose studies of 

 this fish certainly entitle his views to great weight, thinks they probably do so for 

 part of their stay on the bottom. It is not likely, however, that the American 

 mackerel do so, though they may be semi-torpid or at least very sluggish during 

 the cold season, the presence of mackerel in the stomachs of other fish (p. 196), as 

 well as the fact that they sometimes have food in their own stomachs in midwinter, 

 proving that they move about more or less even then, though they certainly feed 

 very little, for not only are most of the European fish trawled at that season empty, 

 but European and American mackerel alike are thin when they reappear in spring. 



Most American students have looked on the rising temperature of spring as 

 determining the date when mackerel quit their winter quarters, an event to be looked 

 for as soon as the water warms to about 45°. Recent European studies, however, 

 show that the date of reappearance is not as closely associated with temperature 

 as has been supposed; and if it be true, as we believe, that the mackerel winter 



48 Ehrenbaum (Rappoits et Proees-Verbaux, Conseil Permanent International pour 1'ExpIoration de la Mer, Vol. XVIII, 

 1914) summarizes what is known of the life history of the European mackerel. 

 " Mackerel are not known so far north. 

 « Rapports et Proces-Verbaux, Conseil Permanent International pour 1'Erploration de la Mer, Vol. XVIII, 1914. 



