FISHES OF THE GULF OF MAINE 207 



In some years, however, spawning is not at its height until July (18S2, for instance), 

 and ripe fish are plentiful until August. 



Any given school spawns over a considerable period, the fish as caught being in 

 varying states — hard, running, or spent. So far as we can learn, however, mackerel 

 have never been found spawning in autumn, though early in November of 1916 we 

 towed a considerable number of eggs in Massachusetts Bay which so closely resem- 

 bled mackerel eggs from the hatchery 62 (p. 208) that we would not have hesitated to 

 identify them as such had they been taken in summer. They may have been the 

 product of a belated fish, but probably of some other Scombroid. 



In the Gulf of St. Lawrence the spawning season is at its height during the last 

 half of June and the first two weeks of July, continuing into August, a fact well 

 recognized by the hook-and-line fishermen of half a century ago, because the ripe fish 

 will not bite at that time, and recently corroborated by the egg catches of the 

 Canadian Fisheries Expedition. 83 



General experience is that ripe mackerel are to be expected wherever large 

 catches are made in the appropriate season — in short, that its spawning range 

 spreads both over the inner parts of the Gulf of Maine and over its offshore banks 

 as well. Massachusetts Bay, in particular, is a prolific center of reproduction in 

 good mackerel years, a fact long known and oft commented upon in print. There 

 is abundant evidence, too, that in such seasons they breed very generally throughout 

 the coastal zone outside the outer islands on the Scotian as well as on the New 

 England side of the gulf, and few though our egg records are, they prove that 

 mackerel spawn over deep basins as well as in the comparatively shoal coastwise 

 waters to which the cod, haddock, and most flat fish repair for breeding. That 

 Nantucket Shoals, Georges Bank, and Browns Bank, like the Scotian banks to the 

 east, are also the sites of a great production of mackerel eggs is proven by the ripe 

 fish caught there, but there is no reason to suppose that they ever breed outside 

 the continental slope. On the other hand, they seldom spawn in estuarine situa- 

 tions, though known to do so on rare occasions. This probably applies even to 

 Casco Bay, for although of old this was thought to be a favorable spawning ground, 

 actual observations in 1897, 64 a year when mackerel were plentiful outside, proved 

 that no eggs were being produced in the bay and that only rarely did any enter with 

 onshore winds. Nor is it likely that mackerel breed successfully in the northern side 

 of the Bay of Fundy, where neither eggs nor larvse have been taken, but some pro- 

 duction may take place near its mouth or on the Scotian side for Huntsman reports 

 eggs at the mouth of the Annapolis River. 



Mackerel, unlike cod or haddock, do not resort to any particular and circum- 

 scribed breeding grounds, but shed their eggs wherever their wandering habits have 

 chanced to lead them when the sexual products ripen, and from this it follows that 

 the precise localities of greatest egg production vary from year to year, depending 

 on the local concentrations of the fish. Thus, the Gulf of Maine may see a tremen- 



" The oil globule averaged very slightly larger — 0.3 to 0.35 mm. as against 0.25 to 0.3 mm. 

 •! Dannevig. Canadian Fisheries Expedition, 1914-15 (1919), p. 8. 

 •' J. P. Moore, 1899. 



