70 BULLETIN OF THE BUREAU OF FISHERIES 



Extensive migrations of fish eggs and of young fishes, in fact of all the plankton, 

 are therefore to be expected as characteristic events in the Gulf of Maine with the 

 dominant anticlockwise eddy that governs its circulation — not their occurrence, 

 but their absence would cry for explanation. And so interesting is this question, 

 and so directly does it bear on the practical problems of the fisheries, that it deserves 

 passing notice, even granted that we can not yet outline the travels of so much as a 

 single species of fish in the gulf. 



No matter how little related the various species are, it is justifiable to consider 

 as a unit all fishes that are subject to similar influences during their pelagic lives, the 

 precise routes they follow at this early age depending not on themselves but on the 

 locations and times of year where and when their eggs are spawned, in relation to 

 the circulation of water in the gulf, and on the duration of the pelagic stage as govern- 

 ing the length of time during which they drift before they abandon this nomadic life 

 for a more stationary habitat on or near bottom. Several of our gadoid and 

 flat fish are particularly suitable for such a combined survey, because while they do 

 not spawn on precisely the same grounds or at just the same seasons, cod, haddock, 

 silver hake, and such common flounders as plaice, dab, and witch, agree in breeding 

 only in the peripheral belt of the gulf and on the offshore banks, seldom, perhaps 

 never, in its central deeps outside the 200-meter contour. As the composite chart 

 (fig. 34) shows, buoyant gadoid and flatfish eggs of one kind or another have 

 been found all around the coastwise belt of the gulf, likewise widespread on Georges 

 and Browns Bank, the richer clusterings of egg records mirroring the greater number 

 of hauls made at particular localities rather than any demonstrable preponderance of 

 eggs as compared with the intervening stretches. If there were no dominant drift 

 of current in one direction or the other, but only the tide to disperse the eggs in these 

 shoaler parts of the gulf, the distribution of the. larvae would simply parallel that of 

 their parent eggs ; but year after year and voyage after voyage we have come to see 

 more and more clearly that such is not the case, but that the young pelagic stages 

 of the cod and flounder families are much less plentiful in the northeastern corner of 

 the gulf than in its southwestern waters in general or in the Massachusetts Bay 

 region (fig. 35) in particular. 



The considerable number of towings carried out along the coast of Maine from 

 spring until autumn, in 1915, fairly rule out the possibility that the discrepancy in 

 distribution between eggs and fry is only apparent and results from an imperfect 

 record. To suppose that the same nets would catch young fish in Massachusetts 

 Bay and as consistently miss them off Mount Desert and to the eastward is absurd ; 

 nor can the depths of the hauls be made responsible, seeing that we have towed at 

 various levels, surface to bottom, as well as vertically, at many stations along the 

 coast. A difference of this sort between the locations where the eggs are spawned 

 and where the resulting larvse are to be found is not a novelty, for Petersen (1892) 

 long ago reported a precisely similar phenomenon for Danish waters. In short, I 

 am convinced that the scarcity of larval and post-larval fishes in the one corner of 

 the gulf as contrasted with their abundance in the other is real. 



It is, of course, possible that the northeast part of the gulf is so ill fitted for a 

 fish nursery that only a small proportion of the pelagic eggs spawned there ever 



