PLANKTON OF THE GULF OF MAINE 73 



Taken by itself, the absence of larvae, contrasted with the presence of eggs, could 

 as well result from a drift of the latter out of the bay before hatching — such, indeed, 

 as the circulation of water would call for — as from their failure to hatch locally or of 

 the larva? to survive. But there are two objections to this view, to my mind unan- 

 swerable; first, that larva? and young fry of these several species are fully as rare along 

 the eastern shores of Maine — that is, in just the waters into which the outflow from the 

 bay debouches — as within the latter; second, that the drift into the southern entrance 

 of the bay would naturally bring with it gadoid and flatfish eggs from the shallows 

 off western Nova Scotia. Some of the cunner (Tautogolabrus) larva? produced in 

 St. Marys Bay, which Huntsman (1922) has found to be an important site of repro- 

 duction for this fish, must likewise find their way into the Bay of Fundy either around 

 Brier Island or through the passages; but so few of them survive the conditions they 

 encounter in the Bay of Fundy, that none have been recorded from all the winter 

 and summer towing which has been done from the St. Andrews station. 



Most of the common fishes that do succeed in breeding in large numbers in the 

 bay lay demersal eggs; for instance, the several sculpins (Cottida?), the lumpfish 

 (Cyclopterus), the rock eel (Pholis gunnellus), the winter flounder {Pseudopleu- 

 ronectes americanus), and the herring. The rosefish (Sebastes) and the eelpout 

 (Zoarces), which are viviparous, produce young far advanced in development. 



The evidence just summarized justifies the hypothesis that while young fish 

 hatched in the bay from demersal eggs, or such as are far developed as to size and 

 fins at hatching, thrive there, most of the very small and helpless larva? produced in 

 the bay from pelagic eggs, or which enter it as immigrants from the south, perish. 

 Hence we may speak of the Bay of Fundy as a deathtrap to buoyant eggs and larva? 

 drifting northward along the eastern shores of the gulf, and it contributes none of 

 these to the coastal waters to the westward. Even the very abundant stock of young 

 herring produced about the mouth of the bay (notably at Grand Manan) do not 

 spread far to the westward, Huntsman having found that they soon become contra- 

 natant and begin to work back against the current, which takes them out of the 

 planktonic category. 



An understanding of the causes that prevent successful development in the 

 bay would make it possible to estimate the probable suitability, from east to west, 

 of the waters along the eastern coast of Maine, where eggs are certainly produced 

 in some abundance but where few larva? have been taken. Huntsman (1918) suggests 

 the violent tidal stirring in the bay as responsible, by preventing vertical strati- 

 fication of the water. The low surface temperature may also be an effective check 

 to species such as the cunner, which spawn in high temperatures. Neither of these 

 factors, however, would seem likely to interfere with the successful breeding of late 

 autumn, winter, or spring spawners — the American pollock and the haddock, for 

 instance. Further light on this interesting question, to which our own work has 

 contributed nothing, is to be expected from the investigations now being carried 

 out at St. Andrews by the Biological Board of Canada. 



From Mount Desert eastward the coastal belt of the gulf more and more closely 

 approximates the Bay of Fundy hydrographically, owing to the increasing strength 

 of the tides and the consequent activity of tidal mixing. Correspondingly, 



