324 A. G. Huntsman 



DIURNAL MIGRATION OF CALAMUS 

 The principal zooplanktont for food of Passamaquoddy herring is the copepod, 

 Calanusfinmarchicus. Its vertical migrations are so complex (Esterly, 1919; Russell, 

 1926; Clarke, 1933; and Gushing, 1951) that local and temporal data seem necessary 

 to show its vertical distribution that may determine how it will be shifted in the 

 Passamaquoddy circulation. Fig. 2 gives an interpretation of the vertical distribution 

 of this species throughout an entire day at Prince Station No. 5, in water about 90 

 metres deep in the Bay of Fundy just outside the main passage leading to Passama- 

 quoddy Bay. It is believed that this is sufficiently representative of the times and places 

 dealt with, except as altered by vertical movements of the water. The interpretation 

 is based, as shown, mainly upon data obtained on September 20, 1926, in closing 

 vertical tows through six different strata at three different times with rapidly increasing 

 light intensity in the morning. It will be evident that these copepods were on the whole 

 more heavily concentrated near the bottom, and least heavily near the surface. 



CHARACTERISTICS OF THE REGION 



Passamaquoddy Bay (Fig. 1) is about five miles wide and ten miles long. On its east 

 side, it is connected with the Bay of Fundy through the relatively short and shallow 

 Letite Passage, and also through the still shallower Little Letite Passage. The main 

 connection, however, is at the south end through the long and tortuous, as well as 

 deep, Western or Head Harbour Passage (also called " Quoddy River "), which 

 virtually forms its mouth. The Passages have very rough, irregular and rocky bottom. 

 The Bay inside is of rather uniform depth, from 20 to 35 metres, but it is still deeper 

 near the Passages. 



Fresh water is discharged into the Bay mainly from the St. Croix, Magaguadavic 

 and Digdeguash Rivers. The St. Croix River discharges into the west side of the Bay 

 near its mouth somewhat more than 2,000 sec/ft from a drainage basin of over 1,300 

 square miles. It is controlled for power purposes, so that in summer the discharge 

 is comparatively steady, ranging for the most part from 500 to 2,000 sec/ft. The 

 Magaguadavic River discharges on the average around 1,000 sec/ft from more than 

 600 square miles into the Bay on its east side near its head, and it is similarly controlled 

 for power purposes. The Digdeguash River, together with other uncontrolled streams, 

 discharges into the head of the Bay the drainage from about 300 square miles. The 

 volume and availability of this discharge may be judged from records made on the 

 Magaguadavic River at Elmcroft (above the level of storage) with a drainage area 

 of about 350 square miles. From 2 to 6 inches of rain fell over the drainage basin 

 on August 26 and 27, 1924, and the rates of discharge on successive days, beginning 

 on August 25, were: 85; 246; 2,890; 2,520; 2,030; 518; 339; 276 sec/ft. Therefore, 

 with heavy rains, the principal increase in river discharge is a day or so after the rain. 

 With other rivers controlled, this is into the head of the Bay. It is to be noted that the 

 discharges of the St. Croix and Magaguadavic Rivers reach the Bay only after having 

 been mixed with sea water in estuaries, which are fifteen and four miles long respec- 

 tively. The estuary of the Digdeguash River is about two miles long. 



The tides of the region are very heavy, the amplitude ranging from 20 to 25 feet. 

 The rough character of the bottom near shore and in the Passages makes the strong 

 tidal currents very effective in mixing the light river water with the heavy sea water. 

 This is evident for the Bay itself in that near the mouth the salinities at the surface and 



