INTRODUCTION 



This memoir is the second part of the report on the oceanographic and biologic 

 survey of the Gulf of Maine, the account of the fishes ' forming the first. 



The vessels of the bureau have carried out the following oceanographic and 

 plankton cruises in the Gulf of Maine since 1912, when the systematic survey was 

 begun : 



Schooner Gram-pus: July to August, 1912; July to August, 1913; July to August, 

 1914; May to October, 1915; and July, August, and October-November, 1916. 



Steamer Albatross: February to May, 1920. 



Steamer Halcyon: December-January, 1920-21 ; March, 1921 ; and August, 1922. 



In addition, tows were taken at intervals during the winter of 1912-13 off 

 Gloucester and between Cape Ann and Cape Elizabeth in April and May, 1913. 

 The Fish Hawk also carried out an extensive program of towing in Massachusetts 

 Bay during the winter and spring of 1924-25, but only a few of the catches have 

 been examined. 



The locations, hydrographic data, and types of nets employed, and the depths 

 of the hauls have been published for all the stations up to May, 1920, in the follow- 

 ing reports : 



July-August, 1912, stations 10001 to 10046, in Bigelow, 1914, p. 135. 



November, 1912-May, 1913, stations 10047 to 10056, in Bigelow, 1914a, p. 416. 



July- August, 1913, stations 10057 to 10061 and 10085 to 10112, in Bigelow, 

 1915, p. 342. 



July-August, 1914, stations 10213 to 10264, in Bigelow, 1917, p. 330. 



May-October, 1915, stations 10266 to 10339, in Bigelow, 1917, p. 331. 



July-November, 1916, stations 10340 to 10355, 10398, and 10399 to 10404, in 

 Bigelow, 1922, p. 176. 



February-May, 1920, stations 20044 to 20129, in United States Bureau of 

 Fisheries Document No. 897 (1921). 



For ready reference the locations of all the tow-net stations for these cruises 

 are given on the accompanying charts (figs. 1 to 6) ; also on figures 7 and 8, the 

 Halcyon tow-net stations of the winter and spring of 1920 and 1921, and of August, 

 1922, the data for which have not yet been published. 



As the value of any regional account of the plankton depends largely on the 

 amount of data available, it may be of interest to add that more than 1,000 tows 

 have been made in the Gulf of Maine region since 1912, at various depths from the 

 surface down to the bottom, some with horizontal and others with vertical nets. In 

 a few cases the tows were made with the horizontal closing net (Bigelow, 1913a). 



The area covered in this report is the same as that covered in the report on the 

 fishes; that is, the oceanic bight from Nantucket on the west to Cape Sable (Nova 



1 Fishes of the Gulf of Maine, by Henry B. Bigelow and William W. Welsh. Ft. I, Vol. XL, Bulletin, O. S. Bureau of 

 Fisheries, 1924 (1925), 567 pp., 278 figs. Washington. Bureau of Fisheries Document No. 965. 



5 



