PLANKTON OF TITE GULF OF MAINE 
189 
localities in this zone during April and May of 1887, while Fowler (1912) reports it in 
great abundance along the New Jersey coast in June, 1911, and early July, 1912. 
In cool summers, such as that of 1916, it continues extremely plentiful along the 
zone of lowest temperature on the shelf, narrowing to the southward to abreast the 
mouth of Chesapeake Bay until the end of summer and becoming much less plentiful 
in autumn, as I have described in a previous report (Bigelow, 1922), but in warm 
years — e. g., 1913 — it practically vanishes south of New York by July (Bigelow, 
1915, p, 269). So far as known, the latitude of Chesapeake Bay may be set as the 
southern limit to its occurrence off the east coast of the United States in numbers 
sufficient to color the plankton at any season. Westward and southward from 
abreast of Cape Sable the zone of abundance for Calanus jinmarchicus is bounded 
offshore by the high temperatures and salinities of the “Gulf Stream,” a boundary 
which fluctuates in location from season to season but which is never far outside the 
edge of the continent. 
Regional distribution in the Gulf of Maine. — In the gulf Calanus fnmarchicus is 
decidedly more oceanic than neritic (p. 35), but exists to some extent in estuarine 
situations as well as offshore. I can offer little first-hand information as to its 
occurrence in inclosed waters, most of our stations having been located out at sea, but 
it has appeared in abundance in Gloucester Harbor (p. 194), and we have likewise 
taken it in abundance in the harbors of Ivittery, Portland (Bigelow, 1914, p. 117), 
Eastport, Provincetown, and in Casco Bay. Doctor McMurrich, in his manu- 
script list, records it regularly at St. Andrews, often in abundance, during the 
winter of 1915-16, from November through April, but only occasionally during the 
later spring, summer, or early autumn. Willey (1921) found it in abundance in the 
mouth of the St. Croix River during the winter of 1916-17, but decidedly rare in the 
winter and spring of 1919 and 1920. If these observations in the St. Andrews 
region apply equally to other parts of the shore line of the gulf, Calanus fnmarchicus 
is to be classed as a winter copepod in estuarine waters, where it has never been 
found in the swarms in which it often occurs in the open sea. Williams (1906) 
similarly found it an abundant winter visitor to Narragansett Bay, and Fish (1925) 
found it in winter and early summer at Woods Hole. 
Outside the estuaries and inside the continental edge, Calanus fnmarchicus is 
universal in the Gulf of Maine, both in deep water and over the shoal banks, but it 
is consistently less abundant in the coastal zone northward and eastward from Cape 
Ann along Maine and Nova Scotia than off Massachusetts Bay and in the basin in 
general. Although the distinction between regions fertile and poor in Calanus is 
apparently least marked in early spring, when the species as a whole is least plentiful 
in the gulf, the chart for February and March, 1920 (fig. 64) shows no frequencies as 
great as 3,000 per square meter anywhere in the peripheral belt inside the 100-meter 
contour between Cape Ann and Cape Sable, with the whole of Georges Bank equally 
barren except for the transitory swarm of Calanus which we encountered over and 
off its southeastern slope on March 12, 1920, as I have described (p. 168). On the 
other hand, all but one of the vertical hauls in the basin and in the channels (eastern 
and northern) yielded more than 1,500 Calanus fnmarchicus per square meter, and 
most of the hauls more than 5,000, with a maximum of 33,700 in the western basin. 
8951—28 13 
