CALANOID COPEPODS FROM THE CENTRAL NORTH 



PACIFIC OCEAN 



By Tai Soo Park, Assisiaiit Scieniisl. Woods Hoi e Oceanographic Institution, Woods Hole, Massachusetts 02543 



ABSTRACT 



A systematic study was made of the calanoid copepods in 

 seven plankton samples collected between lat. 30°00' N. and 

 lat. 42°20' N. along lonji. 155° W. 



Sixty-four species belonging to 17 families are recorded. 

 Measurements, descr ptions, and illustrations are given for 



most of the species. Two species, Euchirella nnispina and 

 Euchaela ztiighli. are described as new, and the hitherto un- 

 known female of Centropages elegans Giesbrecht is described 

 for the first time. Calocalanus tenuis Farran is reported for 

 the first time from the Pacific Ocean. 



The systematics and distribution of the 

 planktonic copepods of the North Pacific have 

 been widely studied, but such investigations 

 have largely been limited to peripheral waters. 

 Outstanding are the papers by: Esterly (1905, 

 1906, 1911, 1913, 1924) and Davis (1949) for 

 the eastern Pacific; by Mori (1937), Tanaka 

 (1956a, 1956b, 1957a, 1957b, 1958, 1960, 1961, 

 1962, 1963, 1964a, 1964b, 1964c), and Vervoort 

 (1946) for the western Pacific; by Brodsky 

 (1950) for the northern North Pacific; and by 

 Grice (1962) for the equatorial Pacific. The 

 copepod fauna of the vast area of the open 

 North Pacific, however, has been relatively 

 little studied, although several early expedi- 

 tions visited the area and yielded lists of local 

 species (Dana, 1853, 1855; Brady, 1883; Gies- 

 brecht, 1895; Wilson, 1942, 1950). 



This paper is devoted to the systematic study 

 of the calanoid copepods in plankton samples 

 from the central North Pacific taken during 

 cruise 29 of the research vessel Hugh M. Smith 

 of the Bureau of Commercial Fisheries. Most 

 of the laboratory work for the study was com- 

 pleted at the Bureau of Commercial Fisheries 

 Biological Laboratory, Honolulu, Hawaii, in 

 1958 and 1959 under a fellowship from the 

 International Cooperation Administration of 

 the United States. 



MATERIALS AND METHODS 



The materials for this study consisted of 

 seven plankton samples collected between lat. 



Published Maich 1968. 



30° 00' N. and lat. 42° 20' N. along long. 155° 

 W. The samples were taken in oblique hauls 

 with a 1-m. (mouth diameter) net. The front 

 and middle sections of the net were made of 

 30XXX silk grit gauze (apertures averaging 

 0.65 mm. in w-idth), and the rear section and 

 bag of 56XXX silk grit gauze (apertures aver- 

 aging 0.31 mm. in width) . The hauls were from 

 a depth of 140 m. and lasted about 30 minutes. 

 The amount of water strained during each haul 

 was measured by a flowmeter in the mouth of 

 the net. The collecting methods for plankton 

 samples adopted by the Biological Laboratory, 

 Honolulu, have been described in detail by King 

 and Demond (1953). 



The pertinent data for each plankton sample 

 are given in table 1. Hydrographic data ob- 

 tained during Hugh M. Smith cruise 29 have 

 been published by Graham (1957). 



Only small quantities of the original samples 

 were examined. Subsamples were obtained by 

 using the Folsom Plankton Sample Splitter 

 (McEwen, Johnson, and Folsom, 1954). The 

 specimens of each species contained in the ali- 

 quot were counted to determine the numerical 

 abundance of the common species. After I had 

 completed the analysis of the subsample, I 

 examined the remainder of the original sample 

 for species not found in the aliquot or to obtain 

 additional specimens, which were often needed 

 to complete the description of a species. Table 

 2 shows the sizes of the subsamples examined, 

 the list of species and the number of specimens 



FISHERY bulletin: VOLUME 66, NO. 3 



527 



